Add bitmap manipulation functions in advance of themes.

skia/ext/image_operations_unittest.cc

Index: skia/ext/image_operations_unittest.cc
===================================================================
--- skia/ext/image_operations_unittest.cc	(revision 13970)
+++ skia/ext/image_operations_unittest.cc	(working copy)
@@ -5,6 +5,7 @@
 #include <stdlib.h>
 
 #include "skia/ext/image_operations.h"
+#include "skia/include/SkColorPriv.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "SkBitmap.h"
 
@@ -145,3 +146,256 @@
     }
   }
 }
+
+// Blend two bitmaps together at 50% alpha and verify that the result
+// is the middle-blend of the two.
+TEST(ImageOperations, CreateBlendedBitmap) {
+  int src_w = 16, src_h = 16;
+  SkBitmap src_a;
+  src_a.setConfig(SkBitmap::kARGB_8888_Config, src_w, src_h);
+  src_a.allocPixels();
+
+  SkBitmap src_b;
+  src_b.setConfig(SkBitmap::kARGB_8888_Config, src_w, src_h);
+  src_b.allocPixels();
+
+  for (int y = 0, i = 0; y < src_h; y++) {
+    for (int x = 0; x < src_w; x++) {
+      *src_a.getAddr32(x, y) = SkColorSetARGB(255, 0, i * 2 % 255, i % 255);
+      *src_b.getAddr32(x, y) =
+          SkColorSetARGB((255 - i) % 255, i % 255, i * 4 % 255, 0);
+      i++;
+    }
+  }
+
+  // Shift to red.
+  SkBitmap blended = skia::ImageOperations::CreateBlendedBitmap(
+    src_a, src_b, 0.5);
+  SkAutoLockPixels srca_lock(src_a);
+  SkAutoLockPixels srcb_lock(src_b);
+  SkAutoLockPixels blended_lock(blended);
+
+  for (int y = 0; y < src_h; y++) {
+    for (int x = 0; x < src_w; x++) {
+      int i = y * src_w + x;
+      EXPECT_EQ((255 + ((255 - i) % 255)) / 2,
+                SkColorGetA(*blended.getAddr32(x, y)));
+      EXPECT_EQ(i % 255 / 2,
+                SkColorGetR(*blended.getAddr32(x, y)));
+      EXPECT_EQ(((i * 2) % 255 + (i * 4) % 255) / 2,
+                SkColorGetG(*blended.getAddr32(x, y)));
+      EXPECT_EQ(i % 255 / 2,
+                SkColorGetB(*blended.getAddr32(x, y)));
+    }
+  }
+}
+
+// Test our masking functions.
+TEST(ImageOperations, CreateMaskedBitmap) {
+  int src_w = 16, src_h = 16;
+
+  SkBitmap src;
+  FillDataToBitmap(src_w, src_h, &src);
+
+  // Generate alpha mask
+  SkBitmap alpha;
+  alpha.setConfig(SkBitmap::kARGB_8888_Config, src_w, src_h);
+  alpha.allocPixels();
+
+  unsigned char* src_data =
+      reinterpret_cast<unsigned char*>(alpha.getAddr32(0, 0));
+  for (int i = 0; i < src_w * src_h; i++) {
+    src_data[i * 4] = SkColorSetARGB(i + 128 % 255,
+                                     i + 128 % 255,
+                                     i + 64 % 255,
+                                     i + 0 % 255);
+  }
+
+  SkBitmap masked = skia::ImageOperations::CreateMaskedBitmap(src, alpha);
+
+  SkAutoLockPixels src_lock(src);
+  SkAutoLockPixels masked_lock(masked);
+  for (int y = 0; y < src_h; y++) {
+    for (int x = 0; x < src_w; x++) {
+      // Test that the alpha is equal.
+      SkColor src_pixel = *src.getAddr32(x, y);
+      SkColor alpha_pixel = *alpha.getAddr32(x, y);
+      SkColor masked_pixel = *masked.getAddr32(x, y);
+
+      // Test that the alpha is equal.
+      int alpha = (alpha_pixel & 0xff000000) >> SK_A32_SHIFT;
+      EXPECT_EQ(alpha, (masked_pixel & 0xff000000) >> SK_A32_SHIFT);
+
+      // Test that the colors are right - SkBitmaps have premultiplied alpha,
+      // so we can't just do a direct comparison.
+      EXPECT_EQ(SkColorGetR(masked_pixel),
+                SkAlphaMul(SkColorGetR(src_pixel), alpha));
+    }
+  }
+}
+
+// Testing blur without reimplementing the blur algorithm here is tough,
+// so we just check to see if the pixels have moved in the direction we
+// think they should move in (and also checking the wrapping behavior).
+// This will allow us to tweak the blur algorithm to suit speed/visual
+// needs without breaking the fundamentals.
+TEST(ImageOperations, CreateBlurredBitmap) {
+  int src_w = 4, src_h = 4;
+  SkBitmap src;
+  src.setConfig(SkBitmap::kARGB_8888_Config, src_w, src_h);
+  src.allocPixels();
+
+  for (int y = 0, i = 0; y < src_h; y++) {
+    for (int x = 0; x < src_w; x++) {
+      int r = (y == 0) ? 255 : 0;  // Make the top row red.
+      int g = (i % 2 == 0) ? 255 : 0;  // Make green alternate in each pixel.
+      int b = (y == src_h - 1) ? 255 : 0;  // Make the bottom row blue.
+
+      *src.getAddr32(x, y) = SkColorSetARGB(255, r, g, b);
+      i++;
+    }
+  }
+
+  // Perform a small blur (enough to shove the values in the direction we
+  // need - more would just be an unneccessary unit test slowdown).
+  SkBitmap blurred = skia::ImageOperations::CreateBlurredBitmap(src, 2);
+
+  SkAutoLockPixels src_lock(src);
+  SkAutoLockPixels blurred_lock(blurred);
+  for (int y = 0, i = 0; y < src_w; y++) {
+    for (int x = 0; x < src_h; x++) {
+      SkColor src_pixel = *src.getAddr32(x, y);
+      SkColor blurred_pixel = *blurred.getAddr32(x, y);
+      if (y == 0) {
+        // We expect our red to have decreased, but our blue to have
+        // increased (from the wrapping from the bottom line).
+        EXPECT_TRUE(SkColorGetR(blurred_pixel) < SkColorGetR(src_pixel));
+        EXPECT_TRUE(SkColorGetB(blurred_pixel) > SkColorGetB(src_pixel));
+      } else if (y == src_h - 1) {
+        // Now for the opposite.
+        EXPECT_TRUE(SkColorGetB(blurred_pixel) < SkColorGetB(src_pixel));
+        EXPECT_TRUE(SkColorGetR(blurred_pixel) > SkColorGetR(src_pixel));
+      }
+
+      // Expect the green channel to have moved towards the center (but
+      // not past it).
+      if (i % 2 == 0) {
+        EXPECT_LT(SkColorGetG(blurred_pixel), SkColorGetG(src_pixel));
+        EXPECT_GE(SkColorGetG(blurred_pixel), static_cast<uint32>(128));
+      } else {
+        EXPECT_GT(SkColorGetG(blurred_pixel), SkColorGetG(src_pixel));
+        EXPECT_LE(SkColorGetG(blurred_pixel), static_cast<uint32>(128));
+      }
+
+      i++;
+    }
+  }
+}
+
+// Make sure that when shifting a bitmap without any shift parameters,
+// the end result is close enough to the original (rounding errors
+// notwithstanding).
+TEST(ImageOperations, CreateHSLShiftedBitmapToSame) {
+  int src_w = 4, src_h = 4;
+  SkBitmap src;
+  src.setConfig(SkBitmap::kARGB_8888_Config, src_w, src_h);
+  src.allocPixels();
+
+  for (int y = 0, i = 0; y < src_h; y++) {
+    for (int x = 0; x < src_w; x++) {
+      *src.getAddr32(x, y) = SkColorSetARGB(i + 128 % 255,
+          i + 128 % 255, i + 64 % 255, i + 0 % 255);
+      i++;
+    }
+  }
+
+  float hsl[3] = { -1, -1, -1 };
+
+  SkBitmap shifted = skia::ImageOperations::CreateHSLShiftedBitmap(src, hsl);
+
+  SkAutoLockPixels src_lock(src);
+  SkAutoLockPixels shifted_lock(shifted);
+
+  for (int y = 0; y < src_w; y++) {
+    for (int x = 0; x < src_h; x++) {
+      SkColor src_pixel = *src.getAddr32(x, y);
+      SkColor shifted_pixel = *shifted.getAddr32(x, y);
+      EXPECT_TRUE(ColorsClose(src_pixel, shifted_pixel));
+    }
+  }
+}
+
+// Shift a blue bitmap to red.
+TEST(ImageOperations, CreateHSLShiftedBitmapHueOnly) {
+  int src_w = 16, src_h = 16;
+  SkBitmap src;
+  src.setConfig(SkBitmap::kARGB_8888_Config, src_w, src_h);
+  src.allocPixels();
+
+  for (int y = 0, i = 0; y < src_h; y++) {
+    for (int x = 0; x < src_w; x++) {
+      *src.getAddr32(x, y) = SkColorSetARGB(255, 0, 0, i % 255);
+      i++;
+    }
+  }
+
+  // Shift to red.
+  float hsl[3] = { 0, -1, -1 };
+
+  SkBitmap shifted = skia::ImageOperations::CreateHSLShiftedBitmap(src, hsl);
+
+  SkAutoLockPixels src_lock(src);
+  SkAutoLockPixels shifted_lock(shifted);
+
+  for (int y = 0, i = 0; y < src_h; y++) {
+    for (int x = 0; x < src_w; x++) {
+      EXPECT_TRUE(ColorsClose(*shifted.getAddr32(x, y),
+                              SkColorSetARGB(255, i % 255, 0, 0)));
+      i++;
+    }
+  }
+}
+
+// Test our cropping.
+TEST(ImageOperations, CreateCroppedBitmap) {
+  int src_w = 16, src_h = 16;
+  SkBitmap src;
+  FillDataToBitmap(src_w, src_h, &src);
+
+  SkBitmap cropped = skia::ImageOperations::CreateTiledBitmap(src, 4, 4,
+                                                              8, 8);
+  ASSERT_EQ(8, cropped.width());
+  ASSERT_EQ(8, cropped.height());
+
+  SkAutoLockPixels src_lock(src);
+  SkAutoLockPixels cropped_lock(cropped);
+  for (int y = 4; y < 12; y++) {
+    for (int x = 4; x < 12; x++) {
+      EXPECT_EQ(*src.getAddr32(x, y),
+                *cropped.getAddr32(x - 4, y - 4));
+    }
+  }
+}
+
+// Test whether our cropping correctly wraps across image boundaries.
+TEST(ImageOperations, CreateCroppedBitmapWrapping) {
+  int src_w = 16, src_h = 16;
+  SkBitmap src;
+  FillDataToBitmap(src_w, src_h, &src);
+
+  SkBitmap cropped = skia::ImageOperations::CreateTiledBitmap(
+      src, src_w / 2, src_h / 2, src_w, src_h);
+  ASSERT_EQ(src_w, cropped.width());
+  ASSERT_EQ(src_h, cropped.height());
+
+  SkAutoLockPixels src_lock(src);
+  SkAutoLockPixels cropped_lock(cropped);
+  for (int y = 0; y < src_h; y++) {
+    for (int x = 0; x < src_w; x++) {
+      EXPECT_EQ(*src.getAddr32(x, y),
+                *cropped.getAddr32((x + src_w / 2) % src_w,
+                                   (y + src_h / 2) % src_h));
+    }
+  }
+}
+