Adding draw looper gm for textblobs

gm/textbloblooper.cpp

+/*
+ * Copyright 2013 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 "Sk2DPathEffect.h"
+#include "SkBlurMask.h"
+#include "SkBlurMaskFilter.h"
+#include "SkColorFilter.h"
+#include "SkCanvas.h"
+#include "SkGradientShader.h"
+#include "SkGraphics.h"
+#include "SkLayerDrawLooper.h"
+#include "SkRandom.h"
+#include "SkTextBlob.h"
+
+namespace skiagm {
+
+static const int kWidth = 1250;
+static const int kHeight = 700;
+
+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());
+
+    const SkScalar advanceX = paint.getTextSize() * 0.85f;
+    const SkScalar advanceY = paint.getTextSize() * 1.5f;
+
+    SkTDArray<SkScalar> pos;
+    for (unsigned i = 0; i < len; ++i) {
+        *pos.append() = x + i * advanceX;
+        *pos.append() = y + i * (advanceY / len);
+    }
+
+    paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
+    const SkTextBlobBuilder::RunBuffer& run = builder->allocRunPos(paint, glyphs.count());
+    memcpy(run.glyphs, glyphs.begin(), glyphs.count() * sizeof(uint16_t));
+    memcpy(run.pos, pos.begin(), len * sizeof(SkScalar) * 2);
+}
+
+typedef void (*LooperProc)(SkPaint*);
+
+struct LooperSettings {
+    SkXfermode::Mode fMode;
+    SkColor          fColor;
+    SkPaint::Style   fStyle;
+    SkScalar         fWidth;
+    SkScalar         fOffset;
+    SkScalar         fSkewX;
+    bool             fEffect;
+};
+
+static void mask_filter(SkPaint* paint) {
+    SkMaskFilter* mf = SkBlurMaskFilter::Create(kNormal_SkBlurStyle,
+                        SkBlurMask::ConvertRadiusToSigma(3.f));
+    paint->setMaskFilter(mf)->unref();
+}
+
+static SkPathEffect* make_tile_effect() {
+    SkMatrix m;
+    m.setScale(1.f, 1.f);
+
+    SkPath path;
+    path.addCircle(0, 0, SkIntToScalar(5));
+
+    return SkPath2DPathEffect::Create(m, path);
+}
+
+static void path_effect(SkPaint* paint) {
+    paint->setPathEffect(make_tile_effect())->unref();
+}
+
+static SkShader* make_shader(const SkRect& bounds) {
+    const SkPoint pts[] = {
+        { bounds.left(), bounds.top() },
+        { bounds.right(), bounds.bottom() },
+    };
+    const SkColor colors[] = {
+        SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE, SK_ColorBLACK,
+        SK_ColorCYAN, SK_ColorMAGENTA, SK_ColorYELLOW,
+    };
+    return SkGradientShader::CreateLinear(pts,
+                                          colors, NULL, SK_ARRAY_COUNT(colors),
+                                          SkShader::kClamp_TileMode);
+}
+
+static void color_filter(SkPaint* paint) {
+    SkRect r;
+    r.setWH(SkIntToScalar(kWidth), 50);
+    paint->setShader(make_shader(r))->unref();
+    paint->setColorFilter(SkColorFilter::CreateLightingFilter(0xF0F0F0, 0))->unref();
+}
+
+static void kitchen_sink(SkPaint* paint) {
+    color_filter(paint);
+    path_effect(paint);
+    mask_filter(paint);
+
+}
+
+static SkLayerDrawLooper* setupLooper(SkLayerDrawLooper::BitFlags bits,
+                                      LooperProc proc,
+                                      const LooperSettings settings[],
+                                      size_t size) {
+    SkLayerDrawLooper::Builder looperBuilder;
+
+    SkLayerDrawLooper::LayerInfo info;
+    info.fPaintBits = bits;
+
+    info.fColorMode = SkXfermode::kSrc_Mode;
+
+    for (size_t i = 0; i < size; i++) {
+        info.fOffset.set(settings[i].fOffset, settings[i].fOffset);
+        SkPaint* paint = looperBuilder.addLayer(info);
+        paint->setXfermodeMode(settings[i].fMode);
+        paint->setColor(settings[i].fColor);
+        paint->setStyle(settings[i].fStyle);
+        paint->setStrokeWidth(settings[i].fWidth);
+        if (settings[i].fEffect) {
+            (*proc)(paint);
+        }
+    }
+    return looperBuilder.detachLooper();
+}
+
+class TextBlobLooperGM : public GM {
+public:
+    TextBlobLooperGM() {}
+
+protected:
+    void onOnceBeforeDraw() override {
+        SkTextBlobBuilder builder;
+
+        // LCD
+        SkPaint paint;
+        paint.setTextSize(32);
+        const char* text = "The quick brown fox jumps over the lazy dog";
+        paint.setSubpixelText(true);
+        paint.setLCDRenderText(true);
+        paint.setAntiAlias(true);
+        add_to_text_blob(&builder, text, paint, 0, 0);
+        fBlob.reset(builder.build());
+
+        // create a looper which sandwhiches an effect in two normal draws
+        LooperSettings looperSandwhich[] = {
+           { SkXfermode::kSrc_Mode, SK_ColorMAGENTA, SkPaint::kFill_Style, 0, 0, 0, false },
+           { SkXfermode::kSrcOver_Mode, 0x88000000, SkPaint::kFill_Style, 0, 10.f, 0, true },
+           { SkXfermode::kSrcOver_Mode, 0x50FF00FF, SkPaint::kFill_Style, 0, 20.f, 0, false },
+        };
+
+        LooperSettings compound[] = {
+            { SkXfermode::kSrc_Mode, SK_ColorWHITE, SkPaint::kStroke_Style, 1.f * 3/4, 0, 0, false },
+            { SkXfermode::kSrc_Mode, SK_ColorRED, SkPaint::kStroke_Style, 4.f, 0, 0, false },
+            { SkXfermode::kSrc_Mode, SK_ColorBLUE, SkPaint::kFill_Style, 0, 0, 0, false },
+            { SkXfermode::kSrcOver_Mode, 0x88000000, SkPaint::kFill_Style, 0, 10.f, 0, true }
+        };
+
+        LooperSettings xfermode[] = {
+            { SkXfermode::kDifference_Mode, SK_ColorWHITE, SkPaint::kFill_Style, 0, 0, 0, false },
+            { SkXfermode::kSrcOver_Mode, 0xFF000000, SkPaint::kFill_Style, 0, 1.f, 0, true },
+            { SkXfermode::kSrcOver_Mode, 0x50FF00FF, SkPaint::kFill_Style, 0, 2.f, 0, false },
+        };
+
+        // NOTE, this should be ignored by textblobs
+        LooperSettings skew[] = {
+            { SkXfermode::kSrc_Mode, SK_ColorRED, SkPaint::kFill_Style, 0, 0, -1.f, false },
+            { SkXfermode::kSrc_Mode, SK_ColorGREEN, SkPaint::kFill_Style, 0, 10.f, -1.f, false },
+            { SkXfermode::kSrc_Mode, SK_ColorBLUE, SkPaint::kFill_Style, 0, 20.f, -1.f, false },
+        };
+
+        LooperSettings kitchenSink[] = {
+            { SkXfermode::kSrc_Mode, SK_ColorWHITE, SkPaint::kStroke_Style, 1.f * 3/4, 0, 0, false },
+            { SkXfermode::kSrc_Mode, SK_ColorBLACK, SkPaint::kFill_Style, 0, 0, 0, false },
+            { SkXfermode::kDifference_Mode, SK_ColorWHITE, SkPaint::kFill_Style, 1.f, 10.f, 0, false },
+            { SkXfermode::kSrc_Mode, SK_ColorWHITE, SkPaint::kFill_Style, 0, 10.f, 0, true },
+            { SkXfermode::kSrcOver_Mode, 0x50FF00FF, SkPaint::kFill_Style, 0, 20.f, 0, false },
+        };
+
+        fLoopers.push_back().reset(setupLooper(SkLayerDrawLooper::kMaskFilter_Bit |
+                                               SkLayerDrawLooper::kXfermode_Bit |
+                                               SkLayerDrawLooper::kStyle_Bit, &mask_filter,
+                                               compound, SK_ARRAY_COUNT(compound)));
+        fLoopers.push_back().reset(setupLooper(SkLayerDrawLooper::kPathEffect_Bit |
+                                               SkLayerDrawLooper::kXfermode_Bit, &path_effect,
+                                               looperSandwhich, SK_ARRAY_COUNT(looperSandwhich)));
+        fLoopers.push_back().reset(setupLooper(SkLayerDrawLooper::kShader_Bit |
+                                               SkLayerDrawLooper::kColorFilter_Bit |
+                                               SkLayerDrawLooper::kXfermode_Bit, &color_filter,
+                                               looperSandwhich, SK_ARRAY_COUNT(looperSandwhich)));
+        fLoopers.push_back().reset(setupLooper(SkLayerDrawLooper::kShader_Bit |
+                                               SkLayerDrawLooper::kColorFilter_Bit |
+                                               SkLayerDrawLooper::kXfermode_Bit, &color_filter,
+                                               xfermode, SK_ARRAY_COUNT(xfermode)));
+        fLoopers.push_back().reset(setupLooper(0, NULL, skew, SK_ARRAY_COUNT(skew)));
+        fLoopers.push_back().reset(setupLooper(SkLayerDrawLooper::kMaskFilter_Bit |
+                                               SkLayerDrawLooper::kShader_Bit |
+                                               SkLayerDrawLooper::kColorFilter_Bit |
+                                               SkLayerDrawLooper::kPathEffect_Bit |
+                                               SkLayerDrawLooper::kStyle_Bit |
+                                               SkLayerDrawLooper::kXfermode_Bit, &kitchen_sink,
+                                               kitchenSink, SK_ARRAY_COUNT(kitchenSink)));
+
+        // Test we respect overrides
+        fLoopers.push_back().reset(setupLooper(0, &kitchen_sink,
+                                               kitchenSink, SK_ARRAY_COUNT(kitchenSink)));
+    }
+
+    SkString onShortName() override {
+        return SkString("textbloblooper");
+    }
+
+    SkISize onISize() override {
+        return SkISize::Make(kWidth, kHeight);
+    }
+
+    void onDraw(SkCanvas* canvas) override {
+
+        canvas->drawColor(SK_ColorGRAY);
+
+        SkPaint paint;
+        canvas->translate(10, 40);
+
+        paint.setTextSize(40);
+
+        SkRect bounds = fBlob->bounds();
+
+        int y = 0;
+        for (int looper = 0; looper < fLoopers.count(); looper++) {
+            paint.setLooper(fLoopers[looper]);
+            canvas->save();
+            canvas->translate(0, SkIntToScalar(y));
+            canvas->drawTextBlob(fBlob, 0, 0, paint);
+            canvas->restore();
+            y += SkScalarFloorToInt(bounds.height());
+        }
+    }
+
+private:
+    SkAutoTUnref<const SkTextBlob> fBlob;
+    SkTArray<SkAutoTUnref<SkLayerDrawLooper>, true> fLoopers;
+
+    typedef GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+DEF_GM( return SkNEW(TextBlobLooperGM); )
+}