SampleColorFilter.cpp 4.4 KB

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  1. /*
  2. * Copyright 2011 Google Inc.
  3. *
  4. * Use of this source code is governed by a BSD-style license that can be
  5. * found in the LICENSE file.
  6. */
  7. #include "include/core/SkCanvas.h"
  8. #include "include/core/SkColorFilter.h"
  9. #include "include/core/SkPaint.h"
  10. #include "include/core/SkShader.h"
  11. #include "samplecode/Sample.h"
  12. #include "tools/ToolUtils.h"
  13. static int inflate5To8(int x) {
  14. return (x << 3) | (x >> 2);
  15. }
  16. static int trunc5(int x) {
  17. return x >> 3;
  18. }
  19. #define SK_R16_BITS 5
  20. #ifdef SK_DEBUG
  21. static int round5_slow(int x) {
  22. int orig = x & 7;
  23. int fake = x >> 5;
  24. int trunc = x >> 3;
  25. int diff = fake - orig;
  26. int bias = 0;
  27. if (diff > 4) {
  28. bias = -1;
  29. } else if (diff < -4) {
  30. bias = 1;
  31. }
  32. return trunc + bias;
  33. }
  34. #endif
  35. static int round5_fast(int x) {
  36. int result = x + 3 - (x >> 5) + (x >> 7);
  37. result >>= 3;
  38. #ifdef SK_DEBUG
  39. {
  40. int r2 = round5_slow(x);
  41. SkASSERT(r2 == result);
  42. }
  43. #endif
  44. return result;
  45. }
  46. static void test_5bits() {
  47. int e0 = 0;
  48. int e1 = 0;
  49. int e2 = 0;
  50. int ae0 = 0;
  51. int ae1 = 0;
  52. int ae2 = 0;
  53. for (int i = 0; i < 256; i++) {
  54. int t0 = trunc5(i);
  55. int t1 = round5_fast(i);
  56. int t2 = trunc5(i);
  57. int v0 = inflate5To8(t0);
  58. int v1 = inflate5To8(t1);
  59. int v2 = inflate5To8(t2);
  60. int err0 = i - v0;
  61. int err1 = i - v1;
  62. int err2 = i - v2;
  63. SkDebugf("--- %3d : trunc=%3d (%2d) round:%3d (%2d) \n"/*new:%d (%2d)\n"*/, i,
  64. v0, err0, v1, err1, v2, err2);
  65. e0 += err0;
  66. e1 += err1;
  67. e2 += err2;
  68. ae0 += SkAbs32(err0);
  69. ae1 += SkAbs32(err1);
  70. ae2 += SkAbs32(err2);
  71. }
  72. SkDebugf("--- trunc: %d %d round: %d %d new: %d %d\n", e0, ae0, e1, ae1, e2, ae2);
  73. }
  74. static SkBitmap createBitmap(int n) {
  75. SkBitmap bitmap;
  76. bitmap.allocN32Pixels(n, n);
  77. bitmap.eraseColor(SK_ColorTRANSPARENT);
  78. SkCanvas canvas(bitmap);
  79. SkRect r;
  80. r.set(0, 0, SkIntToScalar(n), SkIntToScalar(n));
  81. r.inset(SK_Scalar1, SK_Scalar1);
  82. SkPaint paint;
  83. paint.setAntiAlias(true);
  84. paint.setColor(SK_ColorRED);
  85. canvas.drawOval(r, paint);
  86. r.inset(SK_Scalar1*n/4, SK_Scalar1*n/4);
  87. paint.setBlendMode(SkBlendMode::kSrc);
  88. paint.setColor(0x800000FF);
  89. canvas.drawOval(r, paint);
  90. return bitmap;
  91. }
  92. class ColorFilterView : public Sample {
  93. SkBitmap fBitmap;
  94. sk_sp<SkShader> fShader;
  95. enum {
  96. N = 64
  97. };
  98. void onOnceBeforeDraw() override {
  99. fBitmap = createBitmap(N);
  100. fShader = ToolUtils::create_checkerboard_shader(0xFFCCCCCC, 0xFFFFFFFF, 12);
  101. if (false) { // avoid bit rot, suppress warning
  102. test_5bits();
  103. }
  104. }
  105. SkString name() override { return SkString("ColorFilter"); }
  106. void onDrawBackground(SkCanvas* canvas) override {
  107. SkPaint paint;
  108. paint.setShader(fShader);
  109. canvas->drawPaint(paint);
  110. }
  111. void onDrawContent(SkCanvas* canvas) override {
  112. if (false) {
  113. SkPaint p;
  114. p.setAntiAlias(true);
  115. SkRect r = { 20.4f, 10, 20.6f, 20 };
  116. canvas->drawRect(r, p);
  117. r.set(30.9f, 10, 31.1f, 20);
  118. canvas->drawRect(r, p);
  119. return;
  120. }
  121. static const SkBlendMode gModes[] = {
  122. SkBlendMode::kClear,
  123. SkBlendMode::kSrc,
  124. SkBlendMode::kDst,
  125. SkBlendMode::kSrcOver,
  126. SkBlendMode::kDstOver,
  127. SkBlendMode::kSrcIn,
  128. SkBlendMode::kDstIn,
  129. SkBlendMode::kSrcOut,
  130. SkBlendMode::kDstOut,
  131. SkBlendMode::kSrcATop,
  132. SkBlendMode::kDstATop,
  133. SkBlendMode::kXor,
  134. SkBlendMode::kPlus,
  135. SkBlendMode::kModulate,
  136. };
  137. static const SkColor gColors[] = {
  138. 0xFF000000,
  139. 0x80000000,
  140. 0xFF00FF00,
  141. 0x8000FF00,
  142. 0x00000000,
  143. };
  144. float scale = 1.5f;
  145. SkPaint paint;
  146. canvas->translate(N / 8, N / 8);
  147. for (size_t y = 0; y < SK_ARRAY_COUNT(gColors); y++) {
  148. for (size_t x = 0; x < SK_ARRAY_COUNT(gModes); x++) {
  149. paint.setColorFilter(SkColorFilters::Blend(gColors[y], gModes[x]));
  150. canvas->drawBitmap(fBitmap, x * N * 1.25f, y * N * scale, &paint);
  151. }
  152. }
  153. }
  154. };
  155. DEF_SAMPLE( return new ColorFilterView(); )