adding new gm to rotate, translate, and scale textblobs

gm/textblobtransforms.cpp

+/*
+ * 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 TextBlobTransforms : public GM {
+public:
+    // This gm tests that textblobs can be translated, rotated, and scaled
+    TextBlobTransforms() { }
+
+protected:
+    void onOnceBeforeDraw() override {
+        SkTextBlobBuilder builder;
+
+        // make textblob.  To stress distance fields, we choose sizes approrpiately

[jvanverth1, 2015/04/17 13:04:32]

If you want to test distance fields, you'll need to set up the context to do
that. See dftext for an example. Also, "appropriately".

+        SkPaint paint;
+        paint.setTextSize(162);
+        const char* text = "A";
+        sk_tool_utils::set_portable_typeface(&paint);
+
+        SkRect bounds;
+        paint.measureText(text, strlen(text), &bounds);
+        sk_tool_utils::add_to_text_blob(&builder, text, paint, 0, 0);;
+
+        // Medium
+        SkScalar xOffset = bounds.width() + 5;
+        paint.setTextSize(72);
+        text = "B";
+        sk_tool_utils::add_to_text_blob(&builder, text, paint, xOffset, 0);
+
+        paint.measureText(text, strlen(text), &bounds);
+        SkScalar yOffset = bounds.height();
+
+        // Small
+        paint.setTextSize(32);
+        text = "C";
+        sk_tool_utils::add_to_text_blob(&builder, text, paint, xOffset, -yOffset - 10);
+
+        // build
+        fBlob.reset(builder.build());
+    }
+
+    SkString onShortName() override {
+        return SkString("textblobtransforms");
+    }
+
+    SkISize onISize() override {
+        return SkISize::Make(kWidth, kHeight);
+    }
+
+    void onDraw(SkCanvas* canvas) override {
+
+        canvas->drawColor(SK_ColorGRAY);
+
+        SkPaint paint;
+
+        SkRect bounds = fBlob->bounds();
+        canvas->translate(20, 20);
+
+        // 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};
+
+        SkScalar xOffset = SkScalarCeilToScalar(bounds.width());
+        SkScalar yOffset = SkScalarCeilToScalar(bounds.height());
+        // first translate
+        canvas->translate(xOffset, 2 * yOffset);
+        canvas->drawTextBlob(fBlob, 0, 0, paint);
+        canvas->translate(-xOffset, 0);
+        canvas->drawTextBlob(fBlob, 0, 0, paint);
+        canvas->translate(2 * xOffset, 0);
+        canvas->drawTextBlob(fBlob, 0, 0, paint);
+        canvas->translate(-xOffset, -yOffset);
+        canvas->drawTextBlob(fBlob, 0, 0, paint);
+        canvas->translate(0, 2 * yOffset);
+        canvas->drawTextBlob(fBlob, 0, 0, paint);
+
+        // now rotate
+        canvas->translate(4 * xOffset, -yOffset);
+        canvas->rotate(180.f);
+        canvas->drawTextBlob(fBlob, 0, 0, paint);
+        canvas->rotate(-180.f);
+        canvas->translate(0, -yOffset);
+        canvas->rotate(-180.f);
+        canvas->drawTextBlob(fBlob, 0, 0, paint);
+        canvas->rotate(270.f);
+        canvas->drawTextBlob(fBlob, 0, 0, paint);
+        canvas->rotate(-90.f);
+        canvas->translate(-xOffset, yOffset);
+        canvas->rotate(-90.f);
+        canvas->drawTextBlob(fBlob, 0, 0, paint);
+        canvas->rotate(90.f);
+
+        // and scales
+        canvas->translate(- 3 * xOffset, 3 * yOffset);
+        canvas->scale(1.5f, 1.5f);
+        canvas->drawTextBlob(fBlob, 0, 0, paint);
+        canvas->translate(xOffset, 0);
+        canvas->scale(.25f, .25f);
+        canvas->drawTextBlob(fBlob, 0, 0, paint);
+        canvas->translate(xOffset, 0);
+        canvas->scale(3.f, 2.f);
+        canvas->drawTextBlob(fBlob, 0, 0, paint);
+
+        // finally rotates, scales, and translates together
+        canvas->translate(xOffset, 0);
+        canvas->rotate(23.f);
+        canvas->scale(.33f, .5f);
+        canvas->drawTextBlob(fBlob, 0, 0, paint);
+
+        canvas->rotate(-46.f);
+        canvas->translate(xOffset, 0);
+        canvas->scale(1.2f, 1.1f);
+        canvas->drawTextBlob(fBlob, 0, 0, paint);
+
+        canvas->rotate(46.f);
+        canvas->translate(xOffset, 0);
+        canvas->scale(1.1f, 1.2f);
+        canvas->drawTextBlob(fBlob, 0, 0, paint);
+
+        canvas->rotate(46.f);
+        canvas->translate(xOffset, 0);
+        canvas->scale(.95f, 1.1f);
+        canvas->drawTextBlob(fBlob, 0, 0, paint);
+
+        canvas->rotate(46.f);
+        canvas->translate(xOffset, 0);
+        canvas->scale(1.3, .7f);
+        canvas->drawTextBlob(fBlob, 0, 0, paint);
+
+        canvas->rotate(46.f);
+        canvas->translate(xOffset, 0);
+        canvas->scale(.8f, 1.1f);
+        canvas->drawTextBlob(fBlob, 0, 0, paint);
+
+        canvas->rotate(10.f);
+        canvas->translate(xOffset, 0);
+        canvas->scale(1.f, 5.f);
+        canvas->drawTextBlob(fBlob, 0, 0, paint);
+
+        canvas->rotate(5.f);
+        canvas->translate(xOffset, 0);
+        canvas->scale(5.f, 1.f);
+        canvas->drawTextBlob(fBlob, 0, 0, paint);
+    }
+
+private:
+    SkAutoTUnref<const SkTextBlob> fBlob;
+
+    static const int kWidth = 1000;
+    static const int kHeight = 1200;
+
+    typedef GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+DEF_GM( return SkNEW(TextBlobTransforms); )
+}