#Topic Blend_Mode
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#PhraseDef list_of_blend_modes
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SkBlendMode::kClear, SkBlendMode::kSrc, SkBlendMode::kDst, SkBlendMode::kSrcOver,
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SkBlendMode::kDstOver, SkBlendMode::kSrcIn, SkBlendMode::kDstIn,
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SkBlendMode::kSrcOut, SkBlendMode::kDstOut, SkBlendMode::kSrcATop,
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SkBlendMode::kDstATop, SkBlendMode::kXor, SkBlendMode::kPlus,
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SkBlendMode::kModulate, SkBlendMode::kScreen, SkBlendMode::kOverlay,
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SkBlendMode::kDarken, SkBlendMode::kLighten, SkBlendMode::kColorDodge,
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SkBlendMode::kColorBurn, SkBlendMode::kHardLight, SkBlendMode::kSoftLight,
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SkBlendMode::kDifference, SkBlendMode::kExclusion, SkBlendMode::kMultiply,
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SkBlendMode::kHue, SkBlendMode::kSaturation, SkBlendMode::kColor,
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SkBlendMode::kLuminosity
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##
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#Code
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#Populate
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##
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#EnumClass SkBlendMode
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#Line # algorithm combining source and destination pixels ##
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# ------------------------------------------------------------------------------
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#Const kClear 0
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#Line # replaces destination with zero: fully transparent ##
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#Details Clear
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Replaces destination with Alpha and Color components set to zero;
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a fully transparent pixel.
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##
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#Const kSrc 1
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#Line # replaces destination ##
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#Details Src
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Replaces destination with source. Destination alpha and color component values
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are ignored.
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##
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#Const kDst 2
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#Line # preserves destination ##
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#Details Dst
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Preserves destination, ignoring source. Drawing with Paint set to kDst has
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no effect.
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##
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#Const kSrcOver 3
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#Line # source over destination ##
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#Details Src_Over
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Replaces destination with source blended with destination. If source is opaque,
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replaces destination with source. Used as the default Blend_Mode for SkPaint.
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##
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#Const kDstOver 4
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#Line # destination over source ##
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#Details Dst_Over
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Replaces destination with destination blended with source. If destination is opaque,
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has no effect.
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##
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#Const kSrcIn 5
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#Line # source trimmed inside destination ##
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#Details Src_In
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Replaces destination with source using destination opacity.
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##
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#Const kDstIn 6
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#Line # destination trimmed by source ##
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#Details Dst_In
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Scales destination opacity by source opacity.
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##
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#Const kSrcOut 7
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#Line # source trimmed outside destination ##
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#Details Src_Out
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Replaces destination with source using the inverse of destination opacity,
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drawing source fully where destination opacity is zero.
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##
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#Const kDstOut 8
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#Line # destination trimmed outside source ##
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#Details Dst_Out
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Replaces destination opacity with inverse of source opacity. If source is
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transparent, has no effect.
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##
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#Const kSrcATop 9
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#Line # source inside destination blended with destination ##
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#Details Src_Atop
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Blends destination with source using read destination opacity.
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##
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#Const kDstATop 10
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#Line # destination inside source blended with source ##
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#Details Dst_Atop
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Blends destination with source using source opacity.
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##
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#Const kXor 11
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#Line # each of source and destination trimmed outside the other ##
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#Details Xor
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Blends destination by exchanging transparency of the source and destination.
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##
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#Const kPlus 12
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#Line # sum of colors ##
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#Details Plus
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Replaces destination with source and destination added together.
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##
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#Const kModulate 13
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#Line # product of Premultiplied colors; darkens destination ##
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#Details Modulate
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Replaces destination with source and destination multiplied together.
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##
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#Const kScreen 14
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#Line # multiply inverse of pixels, inverting result; brightens destination ##
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#Details Screen
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Replaces destination with inverted source and destination multiplied together.
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##
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#Const kLastCoeffMode 14
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#Line # last Porter_Duff blend mode ##
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##
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#Const kOverlay 15
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#Line # multiply or screen, depending on destination ##
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#Details Overlay
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Replaces destination with multiply or screen, depending on destination.
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##
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#Const kDarken 16
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#Line # darker of source and destination ##
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#Details Darken
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Replaces destination with darker of source and destination.
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##
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#Const kLighten 17
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#Line # lighter of source and destination ##
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#Details Lighten
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Replaces destination with lighter of source and destination.
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##
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#Const kColorDodge 18
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#Line # brighten destination to reflect source ##
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#Details Color_Dodge
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Makes destination brighter to reflect source.
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##
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#Const kColorBurn 19
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#Line # darken destination to reflect source ##
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#Details Color_Burn
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Makes destination darker to reflect source.
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##
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#Const kHardLight 20
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#Line # multiply or screen, depending on source ##
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#Details Hard_Light
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Makes destination lighter or darker, depending on source.
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##
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#Const kSoftLight 21
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#Line # lighten or darken, depending on source ##
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#Details Soft_Light
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Makes destination lighter or darker, depending on source.
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##
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#Const kDifference 22
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#Line # subtract darker from lighter with higher contrast ##
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#Details Difference
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Subtracts darker from lighter with higher contrast.
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##
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#Const kExclusion 23
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#Line # subtract darker from lighter with lower contrast ##
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#Details Exclusion
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Subtracts darker from lighter with lower contrast.
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##
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#Const kMultiply 24
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#Line # multiply source with destination, darkening image ##
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#Details Multiply
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Multiplies source with destination, darkening image.
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##
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#Const kLastSeparableMode 24
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#Line # last blend mode operating separately on components ##
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Last blend mode operating separately on components.
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##
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#Const kHue 25
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#Line # hue of source with saturation and luminosity of destination ##
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#Details Hue
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Replaces hue of destination with hue of source, leaving saturation and luminosity
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unchanged.
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##
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#Const kSaturation 26
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#Line # saturation of source with hue and luminosity of destination ##
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#Details Saturation
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Replaces saturation of destination saturation hue of source, leaving hue and
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luminosity unchanged.
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##
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#Const kColor 27
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#Line # hue and saturation of source with luminosity of destination ##
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#Details Color
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Replaces hue and saturation of destination with hue and saturation of source,
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leaving luminosity unchanged.
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##
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#Const kLuminosity 28
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#Line # luminosity of source with hue and saturation of destination ##
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#Details Luminosity
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Replaces luminosity of destination with luminosity of source, leaving hue and
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saturation unchanged.
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##
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#Const kLastMode 28
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#Line # last valid value ##
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Used by tests to iterate through all valid values.
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##
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#NoExample
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##
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#SeeAlso SkCanvas::drawColor SkCanvas::drawVertices SkPaint SkShader::MakeCompose SkXfermodeImageFilter
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#Subtopic Clear
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#Line # makes destination pixels transparent ##
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SkBlendMode::kClear sets destination to: #Formula # [0, 0] ##.
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Use SkBlendMode::kClear to initialize a buffer to fully transparent pixels when
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creating a mask with irregular edges.
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#Example
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#Description
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SK_ColorYELLOW is ignored because SkBlendMode::kClear ignores the source pixel
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value and the destination pixel value, always setting the destination to zero.
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##
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canvas->saveLayer(nullptr, nullptr);
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canvas->drawColor(SK_ColorYELLOW, SkBlendMode::kClear);
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SkPaint paint;
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for (auto color : { SK_ColorRED, SK_ColorBLUE, SK_ColorGREEN } ) {
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SkColor colors[] = { color, SkColorSetA(color, 0) };
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paint.setShader(SkGradientShader::MakeRadial({ 64, 64}, 100,
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colors, nullptr, SK_ARRAY_COUNT(colors), SkShader::kClamp_TileMode));
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canvas->drawCircle(64, 64, 100, paint);
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canvas->translate(64, 64);
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}
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canvas->restore();
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##
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#SeeAlso SkCanvas::clear
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##
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#Subtopic Src
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#Line # replaces destination, ignoring Alpha ##
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Given: #Formula # Sa ## as source Alpha, #Formula # Sc ## as source Color component;
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SkBlendMode::kSrc sets destination to: #Formula # [Sa, Sc] ##.
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Use SkBlendMode::kSrc to copy one buffer to another. All pixels are copied,
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regardless of source and destination Alpha values. As a parameter to
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SkCanvas::drawAtlas, selects sprites and ignores colors.
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#Example
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#Image 3
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#Description
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SkBlendMode::kSrc does not blend transparent pixels with existing background;
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it punches a transparent hole in the existing image.
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##
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canvas->drawImage(image, 0, 0);
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canvas->clipRect({50, 50, 200, 200});
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SkPaint srcBlend;
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srcBlend.setBlendMode(SkBlendMode::kSrc);
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canvas->saveLayer(nullptr, &srcBlend);
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canvas->drawColor(0);
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SkPaint transRed;
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transRed.setColor(SkColorSetA(SK_ColorRED, 127));
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canvas->drawCircle(125, 125, 75, transRed);
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canvas->restore();
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##
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#SeeAlso SkSurface::draw SkSurface::readPixels
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##
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#Subtopic Dst
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#Line # preserves destination, ignoring source ##
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Given: #Formula # Da ## as destination Alpha, #Formula # Dc ## as destination Color component;
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SkBlendMode::kDst preserves destination set to: #Formula # [Da, Dc] ##.
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Setting Paint Blend_Mode to SkBlendMode::kDst causes drawing with
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Paint to have no effect. As a parameter to SkCanvas::drawAtlas,
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selects colors and ignores sprites.
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#Example
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#Image 3
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SkRSXform xforms[] = { { .5f, 0, 0, 0 }, {0, .5f, 125, 128 } };
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SkRect tex[] = { { 0, 0, 250, 250 }, { 0, 0, 250, 250 } };
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SkColor colors[] = { 0x7f55aa00, 0x7f3333bf };
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canvas->drawAtlas(image.get(), xforms, tex, colors, 2, SkBlendMode::kSrc, nullptr, nullptr);
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canvas->translate(128, 0);
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canvas->drawAtlas(image.get(), xforms, tex, colors, 2, SkBlendMode::kDst, nullptr, nullptr);
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##
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##
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#Subtopic Src_Over
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#Line # blends source with destination ##
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Given: #Formula # Sa ## as source Alpha, #Formula # Sc ## as source Color component,
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#Formula # Da ## as destination Alpha, #Formula # Dc ## as destination Color component;
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SkBlendMode::kSrcOver replaces destination with: #Formula # [Sa + Da * (1 - Sa), Sc + Dc * (1 - Sa)] ##,
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drawing source over destination. SkBlendMode::kSrcOver is the default for Paint.
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SkBlendMode::kSrcOver cannot make destination more transparent; the result will
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be at least as opaque as the less transparent of source and original destination.
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#Example
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SkColor colors[] = { SK_ColorRED, SK_ColorBLUE };
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SkPoint horz[] = { { 0, 0 }, { 256, 0 } };
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SkPaint paint;
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paint.setShader(SkGradientShader::MakeLinear(horz, colors, nullptr, SK_ARRAY_COUNT(colors),
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SkShader::kClamp_TileMode));
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canvas->drawPaint(paint);
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paint.setBlendMode(SkBlendMode::kDstIn);
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SkColor alphas[] = { SK_ColorBLACK, SK_ColorTRANSPARENT };
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SkPoint vert[] = { { 0, 0 }, { 0, 256 } };
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paint.setShader(SkGradientShader::MakeLinear(vert, alphas, nullptr, SK_ARRAY_COUNT(alphas),
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SkShader::kClamp_TileMode));
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canvas->drawPaint(paint);
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canvas->clipRect( { 30, 30, 226, 226 } );
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canvas->drawColor(SkColorSetA(SK_ColorGREEN, 128), SkBlendMode::kSrcOver);
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##
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##
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#Subtopic Dst_Over
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#Line # blends destination with source ##
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Given: #Formula # Sa ## as source Alpha, #Formula # Sc ## as source Color component,
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#Formula # Da ## as destination Alpha, #Formula # Dc ## as destination Color component;
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SkBlendMode::kDstOver replaces destination with: #Formula # [Da + Sa * (1 - Da), Dc + Sc * (1 - Da)] ##,
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drawing destination over source. Has no effect destination if is opaque.
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#Example
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SkColor colors[] = { SK_ColorRED, SK_ColorBLUE };
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SkPoint horz[] = { { 0, 0 }, { 256, 0 } };
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SkPaint paint;
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paint.setShader(SkGradientShader::MakeLinear(horz, colors, nullptr, SK_ARRAY_COUNT(colors),
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SkShader::kClamp_TileMode));
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canvas->drawPaint(paint);
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paint.setBlendMode(SkBlendMode::kDstIn);
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SkColor alphas[] = { SK_ColorBLACK, SK_ColorTRANSPARENT };
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SkPoint vert[] = { { 0, 0 }, { 0, 256 } };
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paint.setShader(SkGradientShader::MakeLinear(vert, alphas, nullptr, SK_ARRAY_COUNT(alphas),
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SkShader::kClamp_TileMode));
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canvas->drawPaint(paint);
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canvas->clipRect( { 30, 30, 226, 226 } );
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canvas->drawColor(SkColorSetA(SK_ColorGREEN, 128), SkBlendMode::kDstOver);
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##
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##
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#Subtopic Src_In
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#Line # source trimmed inside destination ##
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Given: #Formula # Sa ## as source Alpha, #Formula # Sc ## as source Color component,
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#Formula # Da ## as destination Alpha;
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SkBlendMode::kSrcIn replaces destination with: #Formula # [Sa * Da, Sc * Da] ##,
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drawing source with destination opacity.
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#Example
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SkColor colors[] = { SK_ColorRED, SK_ColorBLUE };
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SkPoint horz[] = { { 0, 0 }, { 256, 0 } };
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SkPaint paint;
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paint.setShader(SkGradientShader::MakeLinear(horz, colors, nullptr, SK_ARRAY_COUNT(colors),
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SkShader::kClamp_TileMode));
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canvas->drawPaint(paint);
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paint.setBlendMode(SkBlendMode::kDstIn);
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SkColor alphas[] = { SK_ColorBLACK, SK_ColorTRANSPARENT };
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SkPoint vert[] = { { 0, 0 }, { 0, 256 } };
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paint.setShader(SkGradientShader::MakeLinear(vert, alphas, nullptr, SK_ARRAY_COUNT(alphas),
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SkShader::kClamp_TileMode));
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canvas->drawPaint(paint);
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canvas->clipRect( { 30, 30, 226, 226 } );
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canvas->drawColor(SkColorSetA(SK_ColorGREEN, 128), SkBlendMode::kSrcIn);
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##
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##
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#Subtopic Dst_In
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#Line # destination trimmed by source ##
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Given: #Formula # Sa ## as source Alpha,
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#Formula # Da ## as destination Alpha, #Formula # Dc ## as destination Color component;
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SkBlendMode::kDstIn replaces destination with: #Formula # [Da * Sa, Dc * Sa] ##,
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scaling destination Alpha by source Alpha. Resulting
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destination is visible where source is visible.
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#Example
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SkColor colors[] = { SK_ColorRED, SK_ColorBLUE };
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SkPoint horz[] = { { 0, 0 }, { 256, 0 } };
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SkPaint paint;
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paint.setShader(SkGradientShader::MakeLinear(horz, colors, nullptr, SK_ARRAY_COUNT(colors),
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SkShader::kClamp_TileMode));
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canvas->drawPaint(paint);
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paint.setBlendMode(SkBlendMode::kDstIn);
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SkColor alphas[] = { SK_ColorBLACK, SK_ColorTRANSPARENT };
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SkPoint vert[] = { { 0, 0 }, { 0, 256 } };
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paint.setShader(SkGradientShader::MakeLinear(vert, alphas, nullptr, SK_ARRAY_COUNT(alphas),
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SkShader::kClamp_TileMode));
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canvas->drawPaint(paint);
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canvas->clipRect( { 30, 30, 226, 226 } );
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canvas->drawColor(SkColorSetA(SK_ColorGREEN, 128), SkBlendMode::kDstIn);
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##
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##
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#Subtopic Src_Out
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#Line # source trimmed outside destination ##
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Given: #Formula # Sa ## as source Alpha, #Formula # Sc ## as source Color component,
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#Formula # Da ## as destination Alpha;
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SkBlendMode::kSrcOut replaces destination with: #Formula # [Sa * (1 - Da), Sc * (1 - Da)] ##,
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drawing source fully where destination Alpha is zero. Is destination
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is opaque, has no effect.
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#Example
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SkColor colors[] = { SK_ColorRED, SK_ColorBLUE };
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SkPoint horz[] = { { 0, 0 }, { 256, 0 } };
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SkPaint paint;
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paint.setShader(SkGradientShader::MakeLinear(horz, colors, nullptr, SK_ARRAY_COUNT(colors),
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SkShader::kClamp_TileMode));
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canvas->drawPaint(paint);
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paint.setBlendMode(SkBlendMode::kDstIn);
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SkColor alphas[] = { SK_ColorBLACK, SK_ColorTRANSPARENT };
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SkPoint vert[] = { { 0, 0 }, { 0, 256 } };
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paint.setShader(SkGradientShader::MakeLinear(vert, alphas, nullptr, SK_ARRAY_COUNT(alphas),
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SkShader::kClamp_TileMode));
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canvas->drawPaint(paint);
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canvas->clipRect( { 30, 30, 226, 226 } );
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canvas->drawColor(SkColorSetA(SK_ColorGREEN, 128), SkBlendMode::kSrcOut);
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##
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##
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#Subtopic Dst_Out
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#Line # destination trimmed outside source ##
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Given: #Formula # Sa ## as source Alpha,
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#Formula # Da ## as destination Alpha, #Formula # Dc ## as destination Color component;
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SkBlendMode::kDstOut replaces destination with: #Formula # [Da * (1 - Sa), Dc * (1 - Sa)] ##,
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scaling destination Alpha by source transparency. Resulting
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destination is visible where source is transparent. If source is transparent,
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has no effect.
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#Example
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SkColor colors[] = { SK_ColorRED, SK_ColorBLUE };
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SkPoint horz[] = { { 0, 0 }, { 256, 0 } };
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SkPaint paint;
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paint.setShader(SkGradientShader::MakeLinear(horz, colors, nullptr, SK_ARRAY_COUNT(colors),
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SkShader::kClamp_TileMode));
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canvas->drawPaint(paint);
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paint.setBlendMode(SkBlendMode::kDstIn);
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SkColor alphas[] = { SK_ColorBLACK, SK_ColorTRANSPARENT };
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SkPoint vert[] = { { 0, 0 }, { 0, 256 } };
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paint.setShader(SkGradientShader::MakeLinear(vert, alphas, nullptr, SK_ARRAY_COUNT(alphas),
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SkShader::kClamp_TileMode));
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canvas->drawPaint(paint);
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canvas->clipRect( { 30, 30, 226, 226 } );
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canvas->drawColor(SkColorSetA(SK_ColorGREEN, 128), SkBlendMode::kDstOut);
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##
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##
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#Subtopic Src_Atop
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#Line # source inside destination over destination ##
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Given: #Formula # Sa ## as source Alpha, #Formula # Sc ## as source Color component,
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#Formula # Da ## as destination Alpha, #Formula # Dc ## as destination Color component;
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SkBlendMode::kSrcATop replaces destination with: #Formula # [Da, Sc * Da + Dc * (1 - Sa)] ##,
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replacing opaque destination with opaque source. If source or destination
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is transparent, has no effect.
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#Example
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SkColor colors[] = { SK_ColorRED, SK_ColorBLUE };
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SkPoint horz[] = { { 0, 0 }, { 256, 0 } };
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SkPaint paint;
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paint.setShader(SkGradientShader::MakeLinear(horz, colors, nullptr, SK_ARRAY_COUNT(colors),
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SkShader::kClamp_TileMode));
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canvas->drawPaint(paint);
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paint.setBlendMode(SkBlendMode::kDstIn);
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SkColor alphas[] = { SK_ColorBLACK, SK_ColorTRANSPARENT };
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SkPoint vert[] = { { 0, 0 }, { 0, 256 } };
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paint.setShader(SkGradientShader::MakeLinear(vert, alphas, nullptr, SK_ARRAY_COUNT(alphas),
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SkShader::kClamp_TileMode));
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canvas->drawPaint(paint);
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canvas->clipRect( { 30, 30, 226, 226 } );
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canvas->drawColor(SkColorSetA(SK_ColorGREEN, 128), SkBlendMode::kSrcATop);
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##
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##
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#Subtopic Dst_Atop
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#Line # destination inside source over source ##
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Given: #Formula # Sa ## as source Alpha, #Formula # Sc ## as source Color component,
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#Formula # Da ## as destination Alpha, #Formula # Dc ## as destination Color component;
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SkBlendMode::kDstATop replaces destination with: #Formula # [Sa, Dc * Sa + Sc * (1 - Da)] ##,
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making destination transparent where source is transparent.
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#Example
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SkColor colors[] = { SK_ColorRED, SK_ColorBLUE };
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SkPoint horz[] = { { 0, 0 }, { 256, 0 } };
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SkPaint paint;
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paint.setShader(SkGradientShader::MakeLinear(horz, colors, nullptr, SK_ARRAY_COUNT(colors),
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SkShader::kClamp_TileMode));
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canvas->drawPaint(paint);
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paint.setBlendMode(SkBlendMode::kDstATop);
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SkColor alphas[] = { SK_ColorBLACK, SK_ColorTRANSPARENT };
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SkPoint vert[] = { { 0, 0 }, { 0, 256 } };
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paint.setShader(SkGradientShader::MakeLinear(vert, alphas, nullptr, SK_ARRAY_COUNT(alphas),
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SkShader::kClamp_TileMode));
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canvas->drawPaint(paint);
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canvas->clipRect( { 30, 30, 226, 226 } );
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canvas->drawColor(SkColorSetA(SK_ColorGREEN, 128), SkBlendMode::kSrcATop);
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##
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##
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#Subtopic Xor
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#Line # each of source and destination trimmed outside the other ##
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Given: #Formula # Sa ## as source Alpha, #Formula # Sc ## as source Color component,
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#Formula # Da ## as destination Alpha, #Formula # Dc ## as destination Color component;
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SkBlendMode::kXor replaces destination with:
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#Formula # [Sa + Da - 2 * Sa * Da, Sc * (1 - Da) + Dc * (1 - Sa)] ##,
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exchanging the transparency of the source and destination.
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#Example
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SkPaint paint;
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paint.setBlendMode(SkBlendMode::kXor);
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for (auto color : { SK_ColorRED, SK_ColorBLUE, SK_ColorGREEN } ) {
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SkColor colors[] = { color, SkColorSetA(color, 192), SkColorSetA(color, 128),
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SkColorSetA(color, 0) };
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paint.setShader(SkGradientShader::MakeRadial({ 64, 64}, 100,
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colors, nullptr, SK_ARRAY_COUNT(colors), SkShader::kClamp_TileMode));
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canvas->drawCircle(64, 64, 100, paint);
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canvas->translate(64, 64);
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}
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##
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##
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#Subtopic Plus
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#Line # sum of colors ##
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Given: #Formula # Sa ## as source Alpha, #Formula # Sc ## as source Color component,
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#Formula # Da ## as destination Alpha, #Formula # Dc ## as destination Color component;
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SkBlendMode::kPlus replaces destination with: #Formula # [Sa + Da, Sc + Dc] ##,
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summing the Alpha and Color components.
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#Example
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canvas->drawColor(SK_ColorBLACK);
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SkPaint paint;
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paint.setBlendMode(SkBlendMode::kPlus);
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for (auto color : { SK_ColorRED, SK_ColorBLUE, SK_ColorGREEN } ) {
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SkColor colors[] = { color, SkColorSetA(color, 192), SkColorSetA(color, 128),
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SkColorSetA(color, 0) };
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paint.setShader(SkGradientShader::MakeRadial({ 64, 64}, 100,
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colors, nullptr, SK_ARRAY_COUNT(colors), SkShader::kClamp_TileMode));
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canvas->drawCircle(64, 64, 100, paint);
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canvas->translate(64, 64);
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}
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##
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##
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#Subtopic Modulate
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#Line # product of Premultiplied colors; darkens destination ##
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Given: #Formula # Sa ## as source Alpha, #Formula # Sc ## as source Color component,
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#Formula # Da ## as destination Alpha, #Formula # Dc ## as destination Color component;
|
SkBlendMode::kModulate replaces destination with: #Formula # [Sa * Da, Sc * Dc] ##,
|
scaling Alpha and Color components by the lesser of the values.
|
SkBlendMode::kModulate differs from SkBlendMode::kMultiply in two ways.
|
SkBlendMode::kModulate like SkBlendMode::kSrcATop alters the destination inside
|
the destination area, as if the destination Alpha defined the boundaries of a
|
soft clip. SkBlendMode::kMultiply like SkBlendMode::kSrcOver can alter the
|
destination where the destination is transparent.
|
SkBlendMode::kModulate computes the product of the source and destination using
|
Premultiplied component values. SkBlendMode::kMultiply the product of the source
|
and destination using Unpremultiplied component values.
|
#Example
|
#Description
|
If source and destination are opaque, SkBlendMode::kModulate and
|
SkBlendMode::kMultiply produce the same results.
|
##
|
auto drawSquare = [=](int dx, int dy, SkBlendMode mode, const char* label) -> void {
|
const SkColor colors[] = { SK_ColorBLACK, SK_ColorWHITE };
|
const SkPoint horz[] = { { 0, 0 }, { 128, 0 } };
|
SkPaint paint;
|
paint.setShader(SkGradientShader::MakeLinear(horz, colors, nullptr, SK_ARRAY_COUNT(colors),
|
SkShader::kClamp_TileMode));
|
paint.setBlendMode(mode);
|
canvas->translate(dx, dy);
|
canvas->drawRect({0, 0, 128, 128}, paint);
|
paint.setBlendMode(SkBlendMode::kXor);
|
canvas->drawString(label, 40, 100, paint);
|
};
|
drawSquare(0, 0, SkBlendMode::kSrc, "destination");
|
drawSquare(128, 0, SkBlendMode::kSrc, "");
|
drawSquare(0, 128, SkBlendMode::kSrc, "");
|
canvas->translate(-128, -128);
|
canvas->rotate(90, 0, 128);
|
drawSquare(0, 0, SkBlendMode::kSrc, "source");
|
drawSquare(0, -128, SkBlendMode::kModulate, "modulate");
|
drawSquare(-128, 0, SkBlendMode::kMultiply, "multiply");
|
##
|
##
|
|
#Subtopic Screen
|
#Line # multiply inverse of pixels, inverting result; brightens destination ##
|
Given: #Formula # Sa ## as source Alpha, #Formula # Sc ## as source Color component,
|
#Formula # Da ## as destination Alpha, #Formula # Dc ## as destination Color component;
|
SkBlendMode::kScreen replaces destination with: #Formula # [Sa + Da - Sa * Da, Sc + Dc - Sc * Dc] ##.
|
|
#Example
|
SkColor colors[] = { SK_ColorRED, SK_ColorBLUE };
|
SkPoint horz[] = { { 0, 0 }, { 256, 0 } };
|
SkPaint paint;
|
paint.setShader(SkGradientShader::MakeLinear(horz, colors, nullptr, SK_ARRAY_COUNT(colors),
|
SkShader::kClamp_TileMode));
|
canvas->drawPaint(paint);
|
paint.setBlendMode(SkBlendMode::kDstATop);
|
SkColor alphas[] = { SK_ColorBLACK, SK_ColorTRANSPARENT };
|
SkPoint vert[] = { { 0, 0 }, { 0, 256 } };
|
paint.setShader(SkGradientShader::MakeLinear(vert, alphas, nullptr, SK_ARRAY_COUNT(alphas),
|
SkShader::kClamp_TileMode));
|
canvas->drawPaint(paint);
|
canvas->clipRect( { 30, 30, 226, 226 } );
|
canvas->drawColor(SkColorSetA(SK_ColorGREEN, 128), SkBlendMode::kScreen);
|
##
|
##
|
|
#Subtopic Overlay
|
#Line # multiply or screen, depending on destination ##
|
Given: #Formula # Sa ## as source Alpha, #Formula # Sc ## as source Color component,
|
#Formula # Da ## as destination Alpha, #Formula # Dc ## as destination Color component;
|
SkBlendMode::kOverlay replaces destination with:
|
#Formula # [Sa + Da - Sa * Da, Sc * (1 - Da) + Dc * (1 - Sa) +
|
(2 * Dc <= Da ? 2 * Sc * Dc : Sa * Da - 2 * (Da - Dc) * (Sa - Sc))] ##.
|
#Example
|
SkColor colors[] = { SK_ColorRED, SK_ColorBLUE };
|
SkPoint horz[] = { { 0, 0 }, { 256, 0 } };
|
SkPaint paint;
|
paint.setShader(SkGradientShader::MakeLinear(horz, colors, nullptr, SK_ARRAY_COUNT(colors),
|
SkShader::kClamp_TileMode));
|
canvas->drawPaint(paint);
|
paint.setBlendMode(SkBlendMode::kDstATop);
|
SkColor alphas[] = { SK_ColorBLACK, SK_ColorTRANSPARENT };
|
SkPoint vert[] = { { 0, 0 }, { 0, 256 } };
|
paint.setShader(SkGradientShader::MakeLinear(vert, alphas, nullptr, SK_ARRAY_COUNT(alphas),
|
SkShader::kClamp_TileMode));
|
canvas->drawPaint(paint);
|
canvas->clipRect( { 30, 30, 226, 226 } );
|
canvas->drawColor(SkColorSetA(SK_ColorGREEN, 128), SkBlendMode::kOverlay);
|
##
|
##
|
|
#Subtopic Darken
|
#Line # darker of source and destination ##
|
Given: #Formula # Sa ## as source Alpha, #Formula # Sc ## as source Color component,
|
#Formula # Da ## as destination Alpha, #Formula # Dc ## as destination Color component;
|
SkBlendMode::kDarken replaces destination with:
|
#Formula # [Sa + Da - Sa * Da, Sc + Dc - max(Sc * Da, Dc * Sa)] ##.
|
SkBlendMode::kDarken does not make an image darker; it replaces the destination
|
component with source if source is darker.
|
#Example
|
#Image 3
|
canvas->drawImage(image, 0, 0);
|
SkColor colors[] = { SK_ColorWHITE, SK_ColorBLACK };
|
SkPoint horz[] = { { 0, 0 }, { 256, 0 } };
|
SkPaint paint;
|
paint.setShader(SkGradientShader::MakeLinear(horz, colors, nullptr, SK_ARRAY_COUNT(colors),
|
SkShader::kClamp_TileMode));
|
paint.setBlendMode(SkBlendMode::kDarken);
|
canvas->drawPaint(paint);
|
##
|
##
|
|
#Subtopic Lighten
|
#Line # lighter of source and destination ##
|
Given: #Formula # Sa ## as source Alpha, #Formula # Sc ## as source Color component,
|
#Formula # Da ## as destination Alpha, #Formula # Dc ## as destination Color component;
|
SkBlendMode::kLighten replaces destination with:
|
#Formula # [Sa + Da - Sa * Da, Sc + Dc - min(Sc * Da, Dc * Sa)] ##.
|
SkBlendMode::kDarken does not make an image lighter; it replaces the destination
|
component with source if source is lighter.
|
#Example
|
#Image 3
|
canvas->drawImage(image, 0, 0);
|
SkColor colors[] = { SK_ColorBLACK, SK_ColorWHITE };
|
SkPoint horz[] = { { 0, 0 }, { 256, 0 } };
|
SkPaint paint;
|
paint.setShader(SkGradientShader::MakeLinear(horz, colors, nullptr, SK_ARRAY_COUNT(colors),
|
SkShader::kClamp_TileMode));
|
paint.setBlendMode(SkBlendMode::kLighten);
|
canvas->drawPaint(paint);
|
##
|
##
|
|
#Subtopic Color_Dodge
|
#Line # brighten destination to reflect source ##
|
Given: #Formula # Sa ## as source Alpha, #Formula # Sc ## as source Color component,
|
#Formula # Da ## as destination Alpha, #Formula # Dc ## as destination Color component;
|
SkBlendMode::kColorDodge replaces destination with:
|
#Formula # [Sa + Da - Sa * Da, Dc == 0 ? Sc * (1 - Da) : Sc == Sa ? Sc + Da * (1 - Sa) :
|
Sa * min(Da, Dc * Sa / (Sa - Sc)) + Sc * (1 - Da) + Da * (1 - Sa)] ##,
|
making destination brighter to reflect source.
|
#Example
|
#Image 3
|
canvas->drawImage(image, 0, 0);
|
canvas->clipRect({128, 0, 256, 256});
|
canvas->drawColor(SkColorSetARGB(0x80, 0x90, 0x90, 0x90), SkBlendMode::kColorDodge);
|
##
|
##
|
|
#Subtopic Color_Burn
|
#Line # darken destination to reflect source ##
|
Given: #Formula # Sa ## as source Alpha, #Formula # Sc ## as source Color component,
|
#Formula # Da ## as destination Alpha, #Formula # Dc ## as destination Color component;
|
SkBlendMode::kColorBurn replaces destination with:
|
#Formula # [Sa + Da - Sa * Da, Dc == Da ? Dc + Sc * (1 - Da) : Sc == 0 ? Da * (1 - Sa) :
|
Sa * (Da - min(Da, (Da - Dc) * Sa / Sc)) + Sc * (1 - Da) + Da * (1 - Sa)] ##,
|
making destination darker to reflect source.
|
#Example
|
#Image 3
|
canvas->drawImage(image, 0, 0);
|
canvas->clipRect({128, 0, 256, 256});
|
canvas->drawColor(SkColorSetARGB(0x80, 0x90, 0x90, 0x90), SkBlendMode::kColorBurn);
|
##
|
##
|
|
#Subtopic Hard_Light
|
#Line # multiply or screen, depending on source ##
|
Given: #Formula # Sa ## as source Alpha, #Formula # Sc ## as source Color component,
|
#Formula # Da ## as destination Alpha, #Formula # Dc ## as destination Color component;
|
SkBlendMode::kHardLight replaces destination with:
|
#Formula # [Sa + Da - Sa * Da, Sc * (1 - Da) + Dc * (1 - Sa) +
|
2 * Sc <= Sa ? 2 * Sc * Dc : Sa * Da - 2 * (Da - Dc) * (Sa - Sc)] ##,
|
making destination lighter or darker, depending on source.
|
#Example
|
#Image 3
|
canvas->drawImage(image, 0, 0);
|
const SkColor colors[] = { 0xFFFFFFFF, 0x00000000 };
|
SkPaint paint;
|
paint.setBlendMode(SkBlendMode::kHardLight);
|
paint.setShader(SkGradientShader::MakeRadial({ 128, 128}, 100, colors,
|
nullptr, SK_ARRAY_COUNT(colors), SkShader::kClamp_TileMode));
|
canvas->clipRect({0, 128, 256, 256});
|
canvas->drawPaint(paint);
|
##
|
##
|
|
#Subtopic Soft_Light
|
#Line # lighten or darken, depending on source ##
|
Given: #Formula # Sa ## as source Alpha, #Formula # Sc ## as source Color component,
|
#Formula # Da ## as destination Alpha, #Formula # Dc ## as destination Color component;
|
where #Formula # m = Da > 0 ? Dc / Da : 0 ##;
|
SkBlendMode::kSoftLight replaces destination with: #Formula # [Sa + Da - Sa * Da, Sc / Da + Dc / Sa +
|
(2 * Sc <= Sa ? Dc * (Sa + (2 * Sc - Sa) * (1 - m)) : Dc * Sa + Da * (2 * Sc - Sa) *
|
(4 * Dc <= Da ? (16 * m * m + 4 * m) * (m - 1) + 7 * m : sqrt(m) - m))] ##,
|
making destination lighter or darker, depending on source.
|
#Example
|
#Image 3
|
const SkColor colors[] = { 0xFFFFFFFF, 0x3FFFFFFF };
|
SkPaint paint;
|
paint.setBlendMode(SkBlendMode::kSoftLight);
|
paint.setShader(SkGradientShader::MakeRadial({ 128, 128}, 100, colors,
|
nullptr, SK_ARRAY_COUNT(colors), SkShader::kClamp_TileMode));
|
canvas->drawImage(image, 0, 0);
|
canvas->drawCircle(128, 128, 100, paint);
|
##
|
##
|
|
#Subtopic Difference
|
#Line # subtract darker from lighter with higher contrast ##
|
Given: #Formula # Sa ## as source Alpha, #Formula # Sc ## as source Color component,
|
#Formula # Da ## as destination Alpha, #Formula # Dc ## as destination Color component;
|
SkBlendMode::kDifference replaces destination with:
|
#Formula # [Sa + Da - Sa * Da, Sc + Dc - 2 * min(Sc * Da, Dc * Sa)] ##,
|
replacing destination with lighter less darker.
|
#Example
|
#Image 5
|
canvas->drawImage(image, 0, 0);
|
canvas->drawImage(image, 128, 0);
|
canvas->drawImage(image, 0, 128);
|
canvas->drawImage(image, 128, 128);
|
SkPaint paint;
|
paint.setBlendMode(SkBlendMode::kDstATop);
|
SkColor alphas[] = { SK_ColorBLACK, SK_ColorTRANSPARENT };
|
SkPoint vert[] = { { 0, 0 }, { 0, 256 } };
|
paint.setShader(SkGradientShader::MakeLinear(vert, alphas, nullptr, SK_ARRAY_COUNT(alphas),
|
SkShader::kClamp_TileMode));
|
canvas->drawPaint(paint);
|
canvas->clipRect( { 30, 30, 226, 226 } );
|
canvas->drawColor(0x80bb9977, SkBlendMode::kDifference);
|
##
|
##
|
|
#Subtopic Exclusion
|
#Line # subtract darker from lighter with lower contrast ##
|
Given: #Formula # Sa ## as source Alpha, #Formula # Sc ## as source Color component,
|
#Formula # Da ## as destination Alpha, #Formula # Dc ## as destination Color component;
|
SkBlendMode::kExclusion replaces destination with:
|
#Formula # [Sa + Da - Sa * Da, Sc + Dc - 2 * Sc * Dc] ##,
|
replacing destination with lighter less darker, ignoring Alpha.
|
#Example
|
#Image 5
|
canvas->drawImage(image, 0, 0);
|
canvas->drawImage(image, 128, 0);
|
canvas->drawImage(image, 0, 128);
|
canvas->drawImage(image, 128, 128);
|
SkPaint paint;
|
paint.setBlendMode(SkBlendMode::kDstATop);
|
SkColor alphas[] = { SK_ColorBLACK, SK_ColorTRANSPARENT };
|
SkPoint vert[] = { { 0, 0 }, { 0, 256 } };
|
paint.setShader(SkGradientShader::MakeLinear(vert, alphas, nullptr, SK_ARRAY_COUNT(alphas),
|
SkShader::kClamp_TileMode));
|
canvas->drawPaint(paint);
|
canvas->clipRect( { 30, 30, 226, 226 } );
|
canvas->drawColor(0x80bb9977, SkBlendMode::kExclusion);
|
##
|
##
|
|
#Subtopic Multiply
|
#Line # multiply source with destination, darkening image ##
|
Given: #Formula # Sa ## as source Alpha, #Formula # Sc ## as source Color component,
|
#Formula # Da ## as destination Alpha, #Formula # Dc ## as destination Color component;
|
SkBlendMode::kMultiply replaces destination with:
|
#Formula # [Sa + Da - Sa * Da, Sc * (1 - Da) + Dc * (1 - Sa) + Sc * Dc] ##,
|
the product of Unpremultiplied source and destination.
|
SkBlendMode::kMultiply makes the image darker.
|
#Example
|
#Image 5
|
canvas->drawImage(image, 0, 0);
|
canvas->drawImage(image, 128, 0);
|
canvas->drawImage(image, 0, 128);
|
canvas->drawImage(image, 128, 128);
|
SkPaint paint;
|
paint.setBlendMode(SkBlendMode::kDstATop);
|
SkColor alphas[] = { SK_ColorBLACK, SK_ColorTRANSPARENT };
|
SkPoint vert[] = { { 0, 0 }, { 0, 256 } };
|
paint.setShader(SkGradientShader::MakeLinear(vert, alphas, nullptr, SK_ARRAY_COUNT(alphas),
|
SkShader::kClamp_TileMode));
|
canvas->drawPaint(paint);
|
canvas->clipRect( { 30, 30, 226, 226 } );
|
canvas->drawColor(0x80bb9977, SkBlendMode::kMultiply);
|
##
|
##
|
|
#Subtopic Hue
|
#Line # hue of source with saturation and luminosity of destination ##
|
Given: #Formula # Sa ## as source Alpha, #Formula # S ## as source Color,
|
#Formula # Da ## as destination Alpha, #Formula # D ## as destination Color;
|
SkBlendMode::kHue replaces destination with:
|
#Formula # [Sa + Da - Sa * Da, SetLuminosity(SetSaturation(S, Saturation(D)), Luminosity(D))] ##,
|
source hue, leaving destination luminosity and saturation unchanged.
|
#Example
|
#Image 3
|
canvas->drawImage(image, 0, 0);
|
canvas->drawColor(0xFF00FF00, SkBlendMode::kHue);
|
##
|
##
|
|
#Subtopic Saturation
|
#Line # saturation of source with hue and luminosity of destination ##
|
Given: #Formula # Sa ## as source Alpha, #Formula # S ## as source Color,
|
#Formula # Da ## as destination Alpha, #Formula # D ## as destination Color;
|
SkBlendMode::kHue replaces destination with:
|
#Formula # [Sa + Da - Sa * Da, SetLuminosity(SetSaturation(D, Saturation(S)), Luminosity(D))] ##,
|
source hue, leaving destination luminosity and saturation unchanged.
|
#Example
|
#Image 3
|
canvas->drawImage(image, 0, 0);
|
canvas->drawColor(0xFF00FF00, SkBlendMode::kSaturation);
|
##
|
##
|
|
#Subtopic Color
|
#Line # hue and saturation of source with luminosity of destination ##
|
Given: #Formula # Sa ## as source Alpha, #Formula # S ## as source Color,
|
#Formula # Da ## as destination Alpha, #Formula # D ## as destination Color;
|
SkBlendMode::kColor replaces destination with:
|
#Formula # [Sa + Da - Sa * Da, SetLuminosity(S, Luminosity(D))] ##,
|
source hue and saturation, leaving destination luminosity unchanged.
|
#Example
|
#Image 3
|
canvas->drawImage(image, 0, 0);
|
canvas->drawColor(0xFF00FF00, SkBlendMode::kColor);
|
##
|
##
|
|
#Subtopic Luminosity
|
#Line # luminosity of source with hue and saturation of destination ##
|
Given: #Formula # Sa ## as source Alpha, #Formula # S ## as source Color,
|
#Formula # Da ## as destination Alpha, #Formula # D ## as destination Color;
|
SkBlendMode::kLuminosity replaces destination with:
|
#Formula # [Sa + Da - Sa * Da, SetLuminosity(D, Luminosity(S))] ##,
|
source luminosity, leaving destination hue and saturation unchanged.
|
#Example
|
#Image 3
|
canvas->drawImage(image, 0, 0);
|
canvas->drawColor(0xFF00FF00, SkBlendMode::kLuminosity);
|
##
|
##
|
|
#EnumClass SkBlendMode ##
|
|
# ------------------------------------------------------------------------------
|
|
#Method const char* SkBlendMode_Name(SkBlendMode blendMode)
|
#In Utility
|
#Line # returns mode as C string ##
|
#Populate
|
|
#Example
|
SkDebugf("default blend: SkBlendMode::k%s\n", SkBlendMode_Name(SkPaint().getBlendMode()));
|
#StdOut
|
default blend: SkBlendMode::kSrcOver
|
##
|
##
|
|
#SeeAlso SkBlendMode
|
|
#Method ##
|
|
#Topic Blend_Mode ##
|
