/*
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* Copyright 2011 The Android Open Source Project
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#include "SkScan.h"
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#include "SkBlitter.h"
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#include "SkColorData.h"
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#include "SkFDot6.h"
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#include "SkLineClipper.h"
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#include "SkRasterClip.h"
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#include "SkTo.h"
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#include <utility>
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/* Our attempt to compute the worst case "bounds" for the horizontal and
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vertical cases has some numerical bug in it, and we sometimes undervalue
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our extends. The bug is that when this happens, we will set the clip to
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nullptr (for speed), and thus draw outside of the clip by a pixel, which might
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only look bad, but it might also access memory outside of the valid range
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allcoated for the device bitmap.
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This define enables our fix to outset our "bounds" by 1, thus avoiding the
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chance of the bug, but at the cost of sometimes taking the rectblitter
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case (i.e. not setting the clip to nullptr) when we might not actually need
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to. If we can improve/fix the actual calculations, then we can remove this
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step.
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*/
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#define OUTSET_BEFORE_CLIP_TEST true
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#define HLINE_STACK_BUFFER 100
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static inline int SmallDot6Scale(int value, int dot6) {
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SkASSERT((int16_t)value == value);
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SkASSERT((unsigned)dot6 <= 64);
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return (value * dot6) >> 6;
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}
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//#define TEST_GAMMA
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#ifdef TEST_GAMMA
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static uint8_t gGammaTable[256];
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#define ApplyGamma(table, alpha) (table)[alpha]
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static void build_gamma_table() {
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static bool gInit = false;
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if (gInit == false) {
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for (int i = 0; i < 256; i++) {
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SkFixed n = i * 257;
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n += n >> 15;
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SkASSERT(n >= 0 && n <= SK_Fixed1);
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n = SkFixedSqrt(n);
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n = n * 255 >> 16;
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// SkDebugf("morph %d -> %d\n", i, n);
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gGammaTable[i] = SkToU8(n);
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}
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gInit = true;
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}
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}
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#else
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#define ApplyGamma(table, alpha) SkToU8(alpha)
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#endif
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///////////////////////////////////////////////////////////////////////////////
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static void call_hline_blitter(SkBlitter* blitter, int x, int y, int count,
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U8CPU alpha) {
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SkASSERT(count > 0);
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int16_t runs[HLINE_STACK_BUFFER + 1];
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uint8_t aa[HLINE_STACK_BUFFER];
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aa[0] = ApplyGamma(gGammaTable, alpha);
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do {
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int n = count;
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if (n > HLINE_STACK_BUFFER) {
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n = HLINE_STACK_BUFFER;
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}
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runs[0] = SkToS16(n);
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runs[n] = 0;
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blitter->blitAntiH(x, y, aa, runs);
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x += n;
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count -= n;
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} while (count > 0);
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}
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class SkAntiHairBlitter {
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public:
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SkAntiHairBlitter() : fBlitter(nullptr) {}
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virtual ~SkAntiHairBlitter() {}
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SkBlitter* getBlitter() const { return fBlitter; }
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void setup(SkBlitter* blitter) {
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fBlitter = blitter;
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}
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virtual SkFixed drawCap(int x, SkFixed fy, SkFixed slope, int mod64) = 0;
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virtual SkFixed drawLine(int x, int stopx, SkFixed fy, SkFixed slope) = 0;
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private:
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SkBlitter* fBlitter;
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};
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class HLine_SkAntiHairBlitter : public SkAntiHairBlitter {
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public:
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SkFixed drawCap(int x, SkFixed fy, SkFixed slope, int mod64) override {
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fy += SK_Fixed1/2;
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int y = fy >> 16;
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uint8_t a = (uint8_t)((fy >> 8) & 0xFF);
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// lower line
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unsigned ma = SmallDot6Scale(a, mod64);
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if (ma) {
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call_hline_blitter(this->getBlitter(), x, y, 1, ma);
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}
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// upper line
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ma = SmallDot6Scale(255 - a, mod64);
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if (ma) {
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call_hline_blitter(this->getBlitter(), x, y - 1, 1, ma);
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}
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return fy - SK_Fixed1/2;
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}
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virtual SkFixed drawLine(int x, int stopx, SkFixed fy,
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SkFixed slope) override {
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SkASSERT(x < stopx);
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int count = stopx - x;
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fy += SK_Fixed1/2;
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int y = fy >> 16;
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uint8_t a = (uint8_t)((fy >> 8) & 0xFF);
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// lower line
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if (a) {
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call_hline_blitter(this->getBlitter(), x, y, count, a);
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}
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// upper line
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a = 255 - a;
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if (a) {
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call_hline_blitter(this->getBlitter(), x, y - 1, count, a);
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}
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return fy - SK_Fixed1/2;
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}
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};
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class Horish_SkAntiHairBlitter : public SkAntiHairBlitter {
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public:
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SkFixed drawCap(int x, SkFixed fy, SkFixed dy, int mod64) override {
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fy += SK_Fixed1/2;
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int lower_y = fy >> 16;
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uint8_t a = (uint8_t)((fy >> 8) & 0xFF);
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unsigned a0 = SmallDot6Scale(255 - a, mod64);
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unsigned a1 = SmallDot6Scale(a, mod64);
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this->getBlitter()->blitAntiV2(x, lower_y - 1, a0, a1);
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return fy + dy - SK_Fixed1/2;
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}
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SkFixed drawLine(int x, int stopx, SkFixed fy, SkFixed dy) override {
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SkASSERT(x < stopx);
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fy += SK_Fixed1/2;
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SkBlitter* blitter = this->getBlitter();
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do {
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int lower_y = fy >> 16;
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uint8_t a = (uint8_t)((fy >> 8) & 0xFF);
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blitter->blitAntiV2(x, lower_y - 1, 255 - a, a);
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fy += dy;
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} while (++x < stopx);
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return fy - SK_Fixed1/2;
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}
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};
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class VLine_SkAntiHairBlitter : public SkAntiHairBlitter {
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public:
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SkFixed drawCap(int y, SkFixed fx, SkFixed dx, int mod64) override {
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SkASSERT(0 == dx);
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fx += SK_Fixed1/2;
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int x = fx >> 16;
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int a = (uint8_t)((fx >> 8) & 0xFF);
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unsigned ma = SmallDot6Scale(a, mod64);
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if (ma) {
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this->getBlitter()->blitV(x, y, 1, ma);
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}
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ma = SmallDot6Scale(255 - a, mod64);
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if (ma) {
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this->getBlitter()->blitV(x - 1, y, 1, ma);
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}
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return fx - SK_Fixed1/2;
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}
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SkFixed drawLine(int y, int stopy, SkFixed fx, SkFixed dx) override {
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SkASSERT(y < stopy);
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SkASSERT(0 == dx);
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fx += SK_Fixed1/2;
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int x = fx >> 16;
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int a = (uint8_t)((fx >> 8) & 0xFF);
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if (a) {
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this->getBlitter()->blitV(x, y, stopy - y, a);
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}
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a = 255 - a;
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if (a) {
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this->getBlitter()->blitV(x - 1, y, stopy - y, a);
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}
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return fx - SK_Fixed1/2;
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}
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};
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class Vertish_SkAntiHairBlitter : public SkAntiHairBlitter {
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public:
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SkFixed drawCap(int y, SkFixed fx, SkFixed dx, int mod64) override {
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fx += SK_Fixed1/2;
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int x = fx >> 16;
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uint8_t a = (uint8_t)((fx >> 8) & 0xFF);
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this->getBlitter()->blitAntiH2(x - 1, y,
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SmallDot6Scale(255 - a, mod64), SmallDot6Scale(a, mod64));
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return fx + dx - SK_Fixed1/2;
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}
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SkFixed drawLine(int y, int stopy, SkFixed fx, SkFixed dx) override {
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SkASSERT(y < stopy);
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fx += SK_Fixed1/2;
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do {
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int x = fx >> 16;
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uint8_t a = (uint8_t)((fx >> 8) & 0xFF);
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this->getBlitter()->blitAntiH2(x - 1, y, 255 - a, a);
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fx += dx;
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} while (++y < stopy);
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return fx - SK_Fixed1/2;
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}
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};
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static inline SkFixed fastfixdiv(SkFDot6 a, SkFDot6 b) {
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SkASSERT((SkLeftShift(a, 16) >> 16) == a);
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SkASSERT(b != 0);
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return SkLeftShift(a, 16) / b;
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}
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#define SkBITCOUNT(x) (sizeof(x) << 3)
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#if 1
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// returns high-bit set iff x==0x8000...
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static inline int bad_int(int x) {
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return x & -x;
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}
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static int any_bad_ints(int a, int b, int c, int d) {
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return (bad_int(a) | bad_int(b) | bad_int(c) | bad_int(d)) >> (SkBITCOUNT(int) - 1);
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}
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#else
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static inline int good_int(int x) {
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return x ^ (1 << (SkBITCOUNT(x) - 1));
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}
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static int any_bad_ints(int a, int b, int c, int d) {
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return !(good_int(a) & good_int(b) & good_int(c) & good_int(d));
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}
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#endif
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#ifdef SK_DEBUG
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static bool canConvertFDot6ToFixed(SkFDot6 x) {
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const int maxDot6 = SK_MaxS32 >> (16 - 6);
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return SkAbs32(x) <= maxDot6;
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}
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#endif
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/*
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* We want the fractional part of ordinate, but we want multiples of 64 to
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* return 64, not 0, so we can't just say (ordinate & 63).
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* We basically want to compute those bits, and if they're 0, return 64.
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* We can do that w/o a branch with an extra sub and add.
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*/
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static int contribution_64(SkFDot6 ordinate) {
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#if 0
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int result = ordinate & 63;
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if (0 == result) {
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result = 64;
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}
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#else
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int result = ((ordinate - 1) & 63) + 1;
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#endif
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SkASSERT(result > 0 && result <= 64);
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return result;
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}
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static void do_anti_hairline(SkFDot6 x0, SkFDot6 y0, SkFDot6 x1, SkFDot6 y1,
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const SkIRect* clip, SkBlitter* blitter) {
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// check for integer NaN (0x80000000) which we can't handle (can't negate it)
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// It appears typically from a huge float (inf or nan) being converted to int.
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// If we see it, just don't draw.
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if (any_bad_ints(x0, y0, x1, y1)) {
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return;
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}
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// The caller must clip the line to [-32767.0 ... 32767.0] ahead of time
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// (in dot6 format)
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SkASSERT(canConvertFDot6ToFixed(x0));
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SkASSERT(canConvertFDot6ToFixed(y0));
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SkASSERT(canConvertFDot6ToFixed(x1));
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SkASSERT(canConvertFDot6ToFixed(y1));
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if (SkAbs32(x1 - x0) > SkIntToFDot6(511) || SkAbs32(y1 - y0) > SkIntToFDot6(511)) {
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/* instead of (x0 + x1) >> 1, we shift each separately. This is less
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precise, but avoids overflowing the intermediate result if the
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values are huge. A better fix might be to clip the original pts
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directly (i.e. do the divide), so we don't spend time subdividing
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huge lines at all.
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*/
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int hx = (x0 >> 1) + (x1 >> 1);
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int hy = (y0 >> 1) + (y1 >> 1);
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do_anti_hairline(x0, y0, hx, hy, clip, blitter);
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do_anti_hairline(hx, hy, x1, y1, clip, blitter);
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return;
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}
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int scaleStart, scaleStop;
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int istart, istop;
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SkFixed fstart, slope;
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HLine_SkAntiHairBlitter hline_blitter;
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Horish_SkAntiHairBlitter horish_blitter;
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VLine_SkAntiHairBlitter vline_blitter;
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Vertish_SkAntiHairBlitter vertish_blitter;
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SkAntiHairBlitter* hairBlitter = nullptr;
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if (SkAbs32(x1 - x0) > SkAbs32(y1 - y0)) { // mostly horizontal
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if (x0 > x1) { // we want to go left-to-right
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using std::swap;
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swap(x0, x1);
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swap(y0, y1);
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}
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istart = SkFDot6Floor(x0);
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istop = SkFDot6Ceil(x1);
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fstart = SkFDot6ToFixed(y0);
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if (y0 == y1) { // completely horizontal, take fast case
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slope = 0;
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hairBlitter = &hline_blitter;
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} else {
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slope = fastfixdiv(y1 - y0, x1 - x0);
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SkASSERT(slope >= -SK_Fixed1 && slope <= SK_Fixed1);
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fstart += (slope * (32 - (x0 & 63)) + 32) >> 6;
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hairBlitter = &horish_blitter;
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}
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SkASSERT(istop > istart);
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if (istop - istart == 1) {
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// we are within a single pixel
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scaleStart = x1 - x0;
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SkASSERT(scaleStart >= 0 && scaleStart <= 64);
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scaleStop = 0;
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} else {
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scaleStart = 64 - (x0 & 63);
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scaleStop = x1 & 63;
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}
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if (clip){
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if (istart >= clip->fRight || istop <= clip->fLeft) {
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return;
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}
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if (istart < clip->fLeft) {
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fstart += slope * (clip->fLeft - istart);
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istart = clip->fLeft;
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scaleStart = 64;
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if (istop - istart == 1) {
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// we are within a single pixel
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scaleStart = contribution_64(x1);
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scaleStop = 0;
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}
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}
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if (istop > clip->fRight) {
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istop = clip->fRight;
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scaleStop = 0; // so we don't draw this last column
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}
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SkASSERT(istart <= istop);
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if (istart == istop) {
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return;
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}
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// now test if our Y values are completely inside the clip
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int top, bottom;
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if (slope >= 0) { // T2B
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top = SkFixedFloorToInt(fstart - SK_FixedHalf);
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bottom = SkFixedCeilToInt(fstart + (istop - istart - 1) * slope + SK_FixedHalf);
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} else { // B2T
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bottom = SkFixedCeilToInt(fstart + SK_FixedHalf);
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top = SkFixedFloorToInt(fstart + (istop - istart - 1) * slope - SK_FixedHalf);
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}
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#ifdef OUTSET_BEFORE_CLIP_TEST
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top -= 1;
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bottom += 1;
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#endif
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if (top >= clip->fBottom || bottom <= clip->fTop) {
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return;
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}
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if (clip->fTop <= top && clip->fBottom >= bottom) {
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clip = nullptr;
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}
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}
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} else { // mostly vertical
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if (y0 > y1) { // we want to go top-to-bottom
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using std::swap;
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swap(x0, x1);
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swap(y0, y1);
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}
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istart = SkFDot6Floor(y0);
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istop = SkFDot6Ceil(y1);
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fstart = SkFDot6ToFixed(x0);
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if (x0 == x1) {
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if (y0 == y1) { // are we zero length?
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return; // nothing to do
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}
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slope = 0;
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hairBlitter = &vline_blitter;
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} else {
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slope = fastfixdiv(x1 - x0, y1 - y0);
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SkASSERT(slope <= SK_Fixed1 && slope >= -SK_Fixed1);
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fstart += (slope * (32 - (y0 & 63)) + 32) >> 6;
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hairBlitter = &vertish_blitter;
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}
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SkASSERT(istop > istart);
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if (istop - istart == 1) {
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// we are within a single pixel
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scaleStart = y1 - y0;
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SkASSERT(scaleStart >= 0 && scaleStart <= 64);
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scaleStop = 0;
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} else {
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scaleStart = 64 - (y0 & 63);
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scaleStop = y1 & 63;
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}
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if (clip) {
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if (istart >= clip->fBottom || istop <= clip->fTop) {
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return;
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}
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if (istart < clip->fTop) {
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fstart += slope * (clip->fTop - istart);
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istart = clip->fTop;
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scaleStart = 64;
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if (istop - istart == 1) {
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// we are within a single pixel
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scaleStart = contribution_64(y1);
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scaleStop = 0;
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}
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}
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if (istop > clip->fBottom) {
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istop = clip->fBottom;
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scaleStop = 0; // so we don't draw this last row
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}
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SkASSERT(istart <= istop);
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if (istart == istop)
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return;
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// now test if our X values are completely inside the clip
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int left, right;
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if (slope >= 0) { // L2R
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left = SkFixedFloorToInt(fstart - SK_FixedHalf);
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right = SkFixedCeilToInt(fstart + (istop - istart - 1) * slope + SK_FixedHalf);
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} else { // R2L
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right = SkFixedCeilToInt(fstart + SK_FixedHalf);
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left = SkFixedFloorToInt(fstart + (istop - istart - 1) * slope - SK_FixedHalf);
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}
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#ifdef OUTSET_BEFORE_CLIP_TEST
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left -= 1;
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right += 1;
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#endif
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if (left >= clip->fRight || right <= clip->fLeft) {
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return;
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}
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if (clip->fLeft <= left && clip->fRight >= right) {
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clip = nullptr;
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}
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}
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}
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SkRectClipBlitter rectClipper;
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if (clip) {
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rectClipper.init(blitter, *clip);
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blitter = &rectClipper;
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}
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SkASSERT(hairBlitter);
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hairBlitter->setup(blitter);
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#ifdef SK_DEBUG
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if (scaleStart > 0 && scaleStop > 0) {
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// be sure we don't draw twice in the same pixel
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SkASSERT(istart < istop - 1);
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}
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#endif
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fstart = hairBlitter->drawCap(istart, fstart, slope, scaleStart);
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istart += 1;
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int fullSpans = istop - istart - (scaleStop > 0);
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if (fullSpans > 0) {
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fstart = hairBlitter->drawLine(istart, istart + fullSpans, fstart, slope);
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}
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if (scaleStop > 0) {
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hairBlitter->drawCap(istop - 1, fstart, slope, scaleStop);
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}
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}
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void SkScan::AntiHairLineRgn(const SkPoint array[], int arrayCount, const SkRegion* clip,
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SkBlitter* blitter) {
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if (clip && clip->isEmpty()) {
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return;
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}
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SkASSERT(clip == nullptr || !clip->getBounds().isEmpty());
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#ifdef TEST_GAMMA
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build_gamma_table();
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#endif
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const SkScalar max = SkIntToScalar(32767);
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const SkRect fixedBounds = SkRect::MakeLTRB(-max, -max, max, max);
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SkRect clipBounds;
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if (clip) {
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clipBounds.set(clip->getBounds());
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/* We perform integral clipping later on, but we do a scalar clip first
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to ensure that our coordinates are expressible in fixed/integers.
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antialiased hairlines can draw up to 1/2 of a pixel outside of
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their bounds, so we need to outset the clip before calling the
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clipper. To make the numerics safer, we outset by a whole pixel,
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since the 1/2 pixel boundary is important to the antihair blitter,
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we don't want to risk numerical fate by chopping on that edge.
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*/
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clipBounds.outset(SK_Scalar1, SK_Scalar1);
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}
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for (int i = 0; i < arrayCount - 1; ++i) {
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SkPoint pts[2];
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// We have to pre-clip the line to fit in a SkFixed, so we just chop
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// the line. TODO find a way to actually draw beyond that range.
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if (!SkLineClipper::IntersectLine(&array[i], fixedBounds, pts)) {
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continue;
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}
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if (clip && !SkLineClipper::IntersectLine(pts, clipBounds, pts)) {
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continue;
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}
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SkFDot6 x0 = SkScalarToFDot6(pts[0].fX);
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SkFDot6 y0 = SkScalarToFDot6(pts[0].fY);
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SkFDot6 x1 = SkScalarToFDot6(pts[1].fX);
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SkFDot6 y1 = SkScalarToFDot6(pts[1].fY);
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if (clip) {
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SkFDot6 left = SkMin32(x0, x1);
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SkFDot6 top = SkMin32(y0, y1);
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SkFDot6 right = SkMax32(x0, x1);
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SkFDot6 bottom = SkMax32(y0, y1);
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SkIRect ir;
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ir.set( SkFDot6Floor(left) - 1,
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SkFDot6Floor(top) - 1,
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SkFDot6Ceil(right) + 1,
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SkFDot6Ceil(bottom) + 1);
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if (clip->quickReject(ir)) {
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continue;
|
}
|
if (!clip->quickContains(ir)) {
|
SkRegion::Cliperator iter(*clip, ir);
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const SkIRect* r = &iter.rect();
|
|
while (!iter.done()) {
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do_anti_hairline(x0, y0, x1, y1, r, blitter);
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iter.next();
|
}
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continue;
|
}
|
// fall through to no-clip case
|
}
|
do_anti_hairline(x0, y0, x1, y1, nullptr, blitter);
|
}
|
}
|
|
void SkScan::AntiHairRect(const SkRect& rect, const SkRasterClip& clip,
|
SkBlitter* blitter) {
|
SkPoint pts[5];
|
|
pts[0].set(rect.fLeft, rect.fTop);
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pts[1].set(rect.fRight, rect.fTop);
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pts[2].set(rect.fRight, rect.fBottom);
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pts[3].set(rect.fLeft, rect.fBottom);
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pts[4] = pts[0];
|
SkScan::AntiHairLine(pts, 5, clip, blitter);
|
}
|
|
///////////////////////////////////////////////////////////////////////////////
|
|
typedef int FDot8; // 24.8 integer fixed point
|
|
static inline FDot8 SkFixedToFDot8(SkFixed x) {
|
return (x + 0x80) >> 8;
|
}
|
|
static void do_scanline(FDot8 L, int top, FDot8 R, U8CPU alpha,
|
SkBlitter* blitter) {
|
SkASSERT(L < R);
|
|
if ((L >> 8) == ((R - 1) >> 8)) { // 1x1 pixel
|
blitter->blitV(L >> 8, top, 1, SkAlphaMul(alpha, R - L));
|
return;
|
}
|
|
int left = L >> 8;
|
|
if (L & 0xFF) {
|
blitter->blitV(left, top, 1, SkAlphaMul(alpha, 256 - (L & 0xFF)));
|
left += 1;
|
}
|
|
int rite = R >> 8;
|
int width = rite - left;
|
if (width > 0) {
|
call_hline_blitter(blitter, left, top, width, alpha);
|
}
|
if (R & 0xFF) {
|
blitter->blitV(rite, top, 1, SkAlphaMul(alpha, R & 0xFF));
|
}
|
}
|
|
static void antifilldot8(FDot8 L, FDot8 T, FDot8 R, FDot8 B, SkBlitter* blitter,
|
bool fillInner) {
|
// check for empty now that we're in our reduced precision space
|
if (L >= R || T >= B) {
|
return;
|
}
|
int top = T >> 8;
|
if (top == ((B - 1) >> 8)) { // just one scanline high
|
do_scanline(L, top, R, B - T - 1, blitter);
|
return;
|
}
|
|
if (T & 0xFF) {
|
do_scanline(L, top, R, 256 - (T & 0xFF), blitter);
|
top += 1;
|
}
|
|
int bot = B >> 8;
|
int height = bot - top;
|
if (height > 0) {
|
int left = L >> 8;
|
if (left == ((R - 1) >> 8)) { // just 1-pixel wide
|
blitter->blitV(left, top, height, R - L - 1);
|
} else {
|
if (L & 0xFF) {
|
blitter->blitV(left, top, height, 256 - (L & 0xFF));
|
left += 1;
|
}
|
int rite = R >> 8;
|
int width = rite - left;
|
if (width > 0 && fillInner) {
|
blitter->blitRect(left, top, width, height);
|
}
|
if (R & 0xFF) {
|
blitter->blitV(rite, top, height, R & 0xFF);
|
}
|
}
|
}
|
|
if (B & 0xFF) {
|
do_scanline(L, bot, R, B & 0xFF, blitter);
|
}
|
}
|
|
static void antifillrect(const SkXRect& xr, SkBlitter* blitter) {
|
antifilldot8(SkFixedToFDot8(xr.fLeft), SkFixedToFDot8(xr.fTop),
|
SkFixedToFDot8(xr.fRight), SkFixedToFDot8(xr.fBottom),
|
blitter, true);
|
}
|
|
///////////////////////////////////////////////////////////////////////////////
|
|
void SkScan::AntiFillXRect(const SkXRect& xr, const SkRegion* clip,
|
SkBlitter* blitter) {
|
if (nullptr == clip) {
|
antifillrect(xr, blitter);
|
} else {
|
SkIRect outerBounds;
|
XRect_roundOut(xr, &outerBounds);
|
|
if (clip->isRect()) {
|
const SkIRect& clipBounds = clip->getBounds();
|
|
if (clipBounds.contains(outerBounds)) {
|
antifillrect(xr, blitter);
|
} else {
|
SkXRect tmpR;
|
// this keeps our original edges fractional
|
XRect_set(&tmpR, clipBounds);
|
if (tmpR.intersect(xr)) {
|
antifillrect(tmpR, blitter);
|
}
|
}
|
} else {
|
SkRegion::Cliperator clipper(*clip, outerBounds);
|
const SkIRect& rr = clipper.rect();
|
|
while (!clipper.done()) {
|
SkXRect tmpR;
|
|
// this keeps our original edges fractional
|
XRect_set(&tmpR, rr);
|
if (tmpR.intersect(xr)) {
|
antifillrect(tmpR, blitter);
|
}
|
clipper.next();
|
}
|
}
|
}
|
}
|
|
void SkScan::AntiFillXRect(const SkXRect& xr, const SkRasterClip& clip,
|
SkBlitter* blitter) {
|
if (clip.isBW()) {
|
AntiFillXRect(xr, &clip.bwRgn(), blitter);
|
} else {
|
SkIRect outerBounds;
|
XRect_roundOut(xr, &outerBounds);
|
|
if (clip.quickContains(outerBounds)) {
|
AntiFillXRect(xr, nullptr, blitter);
|
} else {
|
SkAAClipBlitterWrapper wrapper(clip, blitter);
|
AntiFillXRect(xr, &wrapper.getRgn(), wrapper.getBlitter());
|
}
|
}
|
}
|
|
/* This guy takes a float-rect, but with the key improvement that it has
|
already been clipped, so we know that it is safe to convert it into a
|
XRect (fixedpoint), as it won't overflow.
|
*/
|
static void antifillrect(const SkRect& r, SkBlitter* blitter) {
|
SkXRect xr;
|
|
XRect_set(&xr, r);
|
antifillrect(xr, blitter);
|
}
|
|
/* We repeat the clipping logic of AntiFillXRect because the float rect might
|
overflow if we blindly converted it to an XRect. This sucks that we have to
|
repeat the clipping logic, but I don't see how to share the code/logic.
|
|
We clip r (as needed) into one or more (smaller) float rects, and then pass
|
those to our version of antifillrect, which converts it into an XRect and
|
then calls the blit.
|
*/
|
void SkScan::AntiFillRect(const SkRect& origR, const SkRegion* clip,
|
SkBlitter* blitter) {
|
if (clip) {
|
SkRect newR;
|
newR.set(clip->getBounds());
|
if (!newR.intersect(origR)) {
|
return;
|
}
|
|
const SkIRect outerBounds = newR.roundOut();
|
|
if (clip->isRect()) {
|
antifillrect(newR, blitter);
|
} else {
|
SkRegion::Cliperator clipper(*clip, outerBounds);
|
while (!clipper.done()) {
|
newR.set(clipper.rect());
|
if (newR.intersect(origR)) {
|
antifillrect(newR, blitter);
|
}
|
clipper.next();
|
}
|
}
|
} else {
|
antifillrect(origR, blitter);
|
}
|
}
|
|
void SkScan::AntiFillRect(const SkRect& r, const SkRasterClip& clip,
|
SkBlitter* blitter) {
|
if (clip.isBW()) {
|
AntiFillRect(r, &clip.bwRgn(), blitter);
|
} else {
|
SkAAClipBlitterWrapper wrap(clip, blitter);
|
AntiFillRect(r, &wrap.getRgn(), wrap.getBlitter());
|
}
|
}
|
|
///////////////////////////////////////////////////////////////////////////////
|
|
#define SkAlphaMulRound(a, b) SkMulDiv255Round(a, b)
|
|
// calls blitRect() if the rectangle is non-empty
|
static void fillcheckrect(int L, int T, int R, int B, SkBlitter* blitter) {
|
if (L < R && T < B) {
|
blitter->blitRect(L, T, R - L, B - T);
|
}
|
}
|
|
static inline FDot8 SkScalarToFDot8(SkScalar x) {
|
return (int)(x * 256);
|
}
|
|
static inline int FDot8Floor(FDot8 x) {
|
return x >> 8;
|
}
|
|
static inline int FDot8Ceil(FDot8 x) {
|
return (x + 0xFF) >> 8;
|
}
|
|
// 1 - (1 - a)*(1 - b)
|
static inline U8CPU InvAlphaMul(U8CPU a, U8CPU b) {
|
// need precise rounding (not just SkAlphaMul) so that values like
|
// a=228, b=252 don't overflow the result
|
return SkToU8(a + b - SkAlphaMulRound(a, b));
|
}
|
|
static void inner_scanline(FDot8 L, int top, FDot8 R, U8CPU alpha,
|
SkBlitter* blitter) {
|
SkASSERT(L < R);
|
|
if ((L >> 8) == ((R - 1) >> 8)) { // 1x1 pixel
|
FDot8 widClamp = R - L;
|
// border case clamp 256 to 255 instead of going through call_hline_blitter
|
// see skbug/4406
|
widClamp = widClamp - (widClamp >> 8);
|
blitter->blitV(L >> 8, top, 1, InvAlphaMul(alpha, widClamp));
|
return;
|
}
|
|
int left = L >> 8;
|
if (L & 0xFF) {
|
blitter->blitV(left, top, 1, InvAlphaMul(alpha, L & 0xFF));
|
left += 1;
|
}
|
|
int rite = R >> 8;
|
int width = rite - left;
|
if (width > 0) {
|
call_hline_blitter(blitter, left, top, width, alpha);
|
}
|
|
if (R & 0xFF) {
|
blitter->blitV(rite, top, 1, InvAlphaMul(alpha, ~R & 0xFF));
|
}
|
}
|
|
static void innerstrokedot8(FDot8 L, FDot8 T, FDot8 R, FDot8 B,
|
SkBlitter* blitter) {
|
SkASSERT(L < R && T < B);
|
|
int top = T >> 8;
|
if (top == ((B - 1) >> 8)) { // just one scanline high
|
// We want the inverse of B-T, since we're the inner-stroke
|
int alpha = 256 - (B - T);
|
if (alpha) {
|
inner_scanline(L, top, R, alpha, blitter);
|
}
|
return;
|
}
|
|
if (T & 0xFF) {
|
inner_scanline(L, top, R, T & 0xFF, blitter);
|
top += 1;
|
}
|
|
int bot = B >> 8;
|
int height = bot - top;
|
if (height > 0) {
|
if (L & 0xFF) {
|
blitter->blitV(L >> 8, top, height, L & 0xFF);
|
}
|
if (R & 0xFF) {
|
blitter->blitV(R >> 8, top, height, ~R & 0xFF);
|
}
|
}
|
|
if (B & 0xFF) {
|
inner_scanline(L, bot, R, ~B & 0xFF, blitter);
|
}
|
}
|
|
static inline void align_thin_stroke(FDot8& edge1, FDot8& edge2) {
|
SkASSERT(edge1 <= edge2);
|
|
if (FDot8Floor(edge1) == FDot8Floor(edge2)) {
|
edge2 -= (edge1 & 0xFF);
|
edge1 &= ~0xFF;
|
}
|
}
|
|
void SkScan::AntiFrameRect(const SkRect& r, const SkPoint& strokeSize,
|
const SkRegion* clip, SkBlitter* blitter) {
|
SkASSERT(strokeSize.fX >= 0 && strokeSize.fY >= 0);
|
|
SkScalar rx = SkScalarHalf(strokeSize.fX);
|
SkScalar ry = SkScalarHalf(strokeSize.fY);
|
|
// outset by the radius
|
FDot8 outerL = SkScalarToFDot8(r.fLeft - rx);
|
FDot8 outerT = SkScalarToFDot8(r.fTop - ry);
|
FDot8 outerR = SkScalarToFDot8(r.fRight + rx);
|
FDot8 outerB = SkScalarToFDot8(r.fBottom + ry);
|
|
SkIRect outer;
|
// set outer to the outer rect of the outer section
|
outer.set(FDot8Floor(outerL), FDot8Floor(outerT), FDot8Ceil(outerR), FDot8Ceil(outerB));
|
|
SkBlitterClipper clipper;
|
if (clip) {
|
if (clip->quickReject(outer)) {
|
return;
|
}
|
if (!clip->contains(outer)) {
|
blitter = clipper.apply(blitter, clip, &outer);
|
}
|
// now we can ignore clip for the rest of the function
|
}
|
|
// in case we lost a bit with diameter/2
|
rx = strokeSize.fX - rx;
|
ry = strokeSize.fY - ry;
|
|
// inset by the radius
|
FDot8 innerL = SkScalarToFDot8(r.fLeft + rx);
|
FDot8 innerT = SkScalarToFDot8(r.fTop + ry);
|
FDot8 innerR = SkScalarToFDot8(r.fRight - rx);
|
FDot8 innerB = SkScalarToFDot8(r.fBottom - ry);
|
|
// For sub-unit strokes, tweak the hulls such that one of the edges coincides with the pixel
|
// edge. This ensures that the general rect stroking logic below
|
// a) doesn't blit the same scanline twice
|
// b) computes the correct coverage when both edges fall within the same pixel
|
if (strokeSize.fX < 1 || strokeSize.fY < 1) {
|
align_thin_stroke(outerL, innerL);
|
align_thin_stroke(outerT, innerT);
|
align_thin_stroke(innerR, outerR);
|
align_thin_stroke(innerB, outerB);
|
}
|
|
// stroke the outer hull
|
antifilldot8(outerL, outerT, outerR, outerB, blitter, false);
|
|
// set outer to the outer rect of the middle section
|
outer.set(FDot8Ceil(outerL), FDot8Ceil(outerT), FDot8Floor(outerR), FDot8Floor(outerB));
|
|
if (innerL >= innerR || innerT >= innerB) {
|
fillcheckrect(outer.fLeft, outer.fTop, outer.fRight, outer.fBottom,
|
blitter);
|
} else {
|
SkIRect inner;
|
// set inner to the inner rect of the middle section
|
inner.set(FDot8Floor(innerL), FDot8Floor(innerT), FDot8Ceil(innerR), FDot8Ceil(innerB));
|
|
// draw the frame in 4 pieces
|
fillcheckrect(outer.fLeft, outer.fTop, outer.fRight, inner.fTop,
|
blitter);
|
fillcheckrect(outer.fLeft, inner.fTop, inner.fLeft, inner.fBottom,
|
blitter);
|
fillcheckrect(inner.fRight, inner.fTop, outer.fRight, inner.fBottom,
|
blitter);
|
fillcheckrect(outer.fLeft, inner.fBottom, outer.fRight, outer.fBottom,
|
blitter);
|
|
// now stroke the inner rect, which is similar to antifilldot8() except that
|
// it treats the fractional coordinates with the inverse bias (since its
|
// inner).
|
innerstrokedot8(innerL, innerT, innerR, innerB, blitter);
|
}
|
}
|
|
void SkScan::AntiFrameRect(const SkRect& r, const SkPoint& strokeSize,
|
const SkRasterClip& clip, SkBlitter* blitter) {
|
if (clip.isBW()) {
|
AntiFrameRect(r, strokeSize, &clip.bwRgn(), blitter);
|
} else {
|
SkAAClipBlitterWrapper wrap(clip, blitter);
|
AntiFrameRect(r, strokeSize, &wrap.getRgn(), wrap.getBlitter());
|
}
|
}
|
