Start canonicalizing color for all A8 textblobs

BUG=skia:

Review URL: https://codereview.chromium.org/1076593002

3 files changed, 107 insertions, 20 deletions

diff --git a/gm/mixedtextblobs.cpp b/gm/mixedtextblobs.cpp
index 7aaaa52cf0..20b91accfd 100644
--- a/gm/mixedtextblobs.cpp
+++ b/gm/mixedtextblobs.cpp
@@ -16,21 +16,6 @@
 
 namespace skiagm {
 
-static void add_to_text_blob(SkTextBlobBuilder* builder, const char* text, const SkPaint& origPaint,
-                             SkScalar x, SkScalar y) {
-    SkPaint paint(origPaint);
-    SkTDArray<uint16_t> glyphs;
-
-    size_t len = strlen(text);
-    glyphs.append(paint.textToGlyphs(text, len, NULL));
-    paint.textToGlyphs(text, len, glyphs.begin());
-
-    paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
-    const SkTextBlobBuilder::RunBuffer& run = builder->allocRun(paint, glyphs.count(), x, y,
-                                                                NULL);
-    memcpy(run.glyphs, glyphs.begin(), glyphs.count() * sizeof(uint16_t));
-}
-
 static void draw_blob(SkCanvas* canvas, const SkTextBlob* blob, const SkPaint& skPaint,
                       const SkRect& clipRect) {
     SkPaint clipHairline;
@@ -91,7 +76,7 @@ protected:
         paint.measureText(text, strlen(text), &bounds);
 
         SkScalar yOffset = bounds.height();
-        add_to_text_blob(&builder, text, paint, 10, yOffset);
+        sk_tool_utils::add_to_text_blob(&builder, text, paint, 10, yOffset);
         SkScalar corruptedAx = bounds.width();
         SkScalar corruptedAy = yOffset;
 
@@ -107,8 +92,8 @@ protected:
         paint.setSubpixelText(true);
         paint.setLCDRenderText(true);
         paint.measureText(text, strlen(text), &bounds);
-        add_to_text_blob(&builder, text, paint, xOffset - bounds.width() * 0.25f,
-                                                yOffset - bounds.height() * 0.5f);
+        sk_tool_utils::add_to_text_blob(&builder, text, paint, xOffset - bounds.width() * 0.25f,
+                                        yOffset - bounds.height() * 0.5f);
         yOffset += bounds.height();
 
         // color emoji
@@ -117,13 +102,14 @@ protected:
         paint.setTypeface(fEmojiTypeface);
         text = fEmojiText;
         paint.measureText(text, strlen(text), &bounds);
-        add_to_text_blob(&builder, text, paint, xOffset - bounds.width() * 0.3f, yOffset);
+        sk_tool_utils::add_to_text_blob(&builder, text, paint, xOffset - bounds.width() * 0.3f,
+                                        yOffset);
 
         // Corrupted font
         paint.setTextSize(12);
         text = "aA";
         paint.setTypeface(fReallyBigATypeface);
-        add_to_text_blob(&builder, text, paint, corruptedAx, corruptedAy);
+        sk_tool_utils::add_to_text_blob(&builder, text, paint, corruptedAx, corruptedAy);
         fBlob.reset(builder.build());
     }
 
diff --git a/gm/textblobcolortrans.cpp b/gm/textblobcolortrans.cpp
new file mode 100644
index 0000000000..cb4686e6e7
--- /dev/null
+++ b/gm/textblobcolortrans.cpp
@@ -0,0 +1,100 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "gm.h"
+
+#include "Resources.h"
+#include "SkCanvas.h"
+#include "SkGradientShader.h"
+#include "SkStream.h"
+#include "SkTextBlob.h"
+#include "SkTypeface.h"
+
+namespace skiagm {
+class TextBlobColorTrans : public GM {
+public:
+    // This gm tests that textblobs can be translated and have their colors regenerated
+    // correctly.  With smaller atlas sizes, it can also trigger regeneration of texture coords on
+    // the GPU backend
+    TextBlobColorTrans() { }
+
+protected:
+    void onOnceBeforeDraw() override {
+        SkTextBlobBuilder builder;
+
+        // make textblob
+        // Large text is used to trigger atlas eviction
+        SkPaint paint;
+        paint.setTextSize(256);
+        const char* text = "AB";
+        sk_tool_utils::set_portable_typeface(&paint);
+
+        SkRect bounds;
+        paint.measureText(text, strlen(text), &bounds);
+
+        SkScalar yOffset = bounds.height();
+        sk_tool_utils::add_to_text_blob(&builder, text, paint, 0, yOffset - 30);
+
+        // A8
+        paint.setTextSize(28);
+        text = "The quick brown fox jumps over the lazy dog.";
+        paint.setSubpixelText(false);
+        paint.setLCDRenderText(false);
+        paint.measureText(text, strlen(text), &bounds);
+        sk_tool_utils::add_to_text_blob(&builder, text, paint, 0, yOffset - 8);
+
+        // build
+        fBlob.reset(builder.build());
+    }
+
+    SkString onShortName() override {
+        return SkString("textblobcolortrans");
+    }
+
+    SkISize onISize() override {
+        return SkISize::Make(kWidth, kHeight);
+    }
+
+    void onDraw(SkCanvas* canvas) override {
+
+        canvas->drawColor(SK_ColorGRAY);
+
+        SkPaint paint;
+        canvas->translate(10, 40);
+
+        SkRect bounds = fBlob->bounds();
+
+        // Colors were chosen to map to pairs of canonical colors.  The GPU Backend will cache A8
+        // Texture Blobs based on the canonical color they map to.  Canonical colors are used to
+        // create masks.  For A8 there are 8 of them.
+        SkColor colors[] = {SK_ColorCYAN, SK_ColorLTGRAY, SK_ColorYELLOW, SK_ColorWHITE};
+
+        size_t count = SK_ARRAY_COUNT(colors);
+        size_t colorIndex = 0;
+        for (int y = 0; y + SkScalarFloorToInt(bounds.height()) < kHeight;
+             y += SkScalarFloorToInt(bounds.height())) {
+            paint.setColor(colors[colorIndex++ % count]);
+            canvas->save();
+            canvas->translate(0, SkIntToScalar(y));
+            canvas->drawTextBlob(fBlob, 0, 0, paint);
+            canvas->restore();
+        }
+    }
+
+private:
+    SkAutoTUnref<const SkTextBlob> fBlob;
+
+    static const int kWidth = 675;
+    static const int kHeight = 1600;
+
+    typedef GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+DEF_GM( return SkNEW(TextBlobColorTrans); )
+}
diff --git a/gm/textbloblooper.cpp b/gm/textbloblooper.cpp
index 253945f123..2fbd30b3cf 100644
--- a/gm/textbloblooper.cpp
+++ b/gm/textbloblooper.cpp
@@ -23,6 +23,7 @@ namespace skiagm {
 static const int kWidth = 1250;
 static const int kHeight = 700;
 
+// Unlike the variant in sk_tool_utils, this version positions the glyphs on a diagonal
 static void add_to_text_blob(SkTextBlobBuilder* builder, const char* text, const SkPaint& origPaint,
                              SkScalar x, SkScalar y) {
     SkPaint paint(origPaint);