add gm: colorwheel

gm/colorwheel.cpp

+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "Resources.h"
+#include "SkData.h"
+#include "SkDecodingImageGenerator.h"
+#include "gm.h"
+
+static void checkerboard(SkCanvas* canvas, int w, int h) {
+    SkASSERT(w > 0);
+    SkASSERT(h > 0);
+    w = ((w - 1) | 0xF) + 1;
+    h = ((h - 1) | 0xF) + 1;
+    SkPaint light;
+    light.setColor(0xFF999999);
+    canvas->drawRect(SkRect::MakeXYWH(0, 0, w, h), light);
+    SkPaint dark;
+    dark.setColor(0xFF666666);
+    for (int y = 0; y < w; y += 16) {
+        SkScalar ty = SkIntToScalar(y);
+        for (int x = 0; x < h; x += 16) {
+            SkScalar tx = SkIntToScalar(x);
+            canvas->drawRect(SkRect::MakeXYWH(tx + 0, ty + 0, 8, 8), dark);
+            canvas->drawRect(SkRect::MakeXYWH(tx + 8, ty + 8, 8, 8), dark);
+        }
+    }
+}
+
+/*
+  This GM tests whether the image decoders properly decode each color
+  channel.  Four copies of the same image should appear in the GM, and
+  the letter R should be red, B should be blue, G green, C cyan, M
+  magenta, Y yellow, and K black. In all but the JPEG version of the
+  image, the letters should be on a white disc on a transparent
+  background (rendered as a checkerboard).  The JPEG image has a grey
+  background and compression artifacts.
+ */
+DEF_SIMPLE_GM(colorwheel, canvas, 256, 256) {
+    canvas->clear(SK_ColorWHITE);
+    checkerboard(canvas, 256, 256);
+    SkBitmap bitmap;
+    if (GetResourceAsBitmap("color_wheel.png", &bitmap)) {

[mtklein, 2014/10/24 17:28:44]

Might want SkAssertResult in here somewhere?

[hal.canary, 2014/10/24 18:01:14]

Done.

+        canvas->drawBitmap(bitmap, 0, 0);  // top left
+    }
+    if (GetResourceAsBitmap("color_wheel.gif", &bitmap)) {
+        canvas->drawBitmap(bitmap, 128, 0);  // top right
+    }
+    if (GetResourceAsBitmap("color_wheel.webp", &bitmap)) {
+        canvas->drawBitmap(bitmap, 0, 128);  // bottom left
+    }
+    if (GetResourceAsBitmap("color_wheel.jpg", &bitmap)) {
+        canvas->drawBitmap(bitmap, 128, 128);  // bottom right
+    }
+}