SkPictureImageGenerator

gm/pictureimagegenerator.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 "SkBitmap.h"
+#include "SkCanvas.h"
+#include "SkGradientShader.h"
+#include "SkImageGenerator.h"
+#include "SkPaint.h"
+#include "SkPathOps.h"
+#include "SkPicture.h"
+#include "SkPictureImageGenerator.h"
+#include "SkPictureRecorder.h"
+
+namespace {
+

[robertphillips, 2015/07/20 17:32:43]

static ? no namespace ?

[f(malita), 2015/07/20 20:13:38]

Done.

+void draw_vector_logo(SkCanvas* canvas, const SkRect& viewBox) {
+    static const char kSkiaStr[] = "SKIA";
+    static const SkScalar kGradientPad = .1f;
+    static const SkScalar kVerticalSpacing = 0.25f;
+    static const SkScalar kAccentScale = 1.20;
+
+    SkPaint paint;
+    paint.setAntiAlias(true);
+    paint.setSubpixelText(true);
+    paint.setFakeBoldText(true);
+    sk_tool_utils::set_portable_typeface_always(&paint);
+
+    SkPath path;
+    SkRect iBox, skiBox, skiaBox;
+    paint.getTextPath("SKI", 3, 0, 0, &path);
+    TightBounds(path, &skiBox);
+    paint.getTextPath("I", 1, 0, 0, &path);
+    TightBounds(path, &iBox);
+    iBox.offsetTo(skiBox.fRight - iBox.width(), iBox.fTop);
+
+    const unsigned textLen = strlen(kSkiaStr);
+    paint.getTextPath(kSkiaStr, textLen, 0, 0, &path);
+    TightBounds(path, &skiaBox);
+    skiaBox.outset(0, 2 * iBox.width() * (kVerticalSpacing + 1));
+
+    const SkScalar accentSize = iBox.width() * kAccentScale;
+    const SkScalar underlineY = iBox.bottom() + (kVerticalSpacing + sqrt(3) / 2) * accentSize;
+    SkMatrix m;
+    m.setRectToRect(skiaBox, viewBox, SkMatrix::kFill_ScaleToFit);
+    canvas->concat(m);
+
+    canvas->drawCircle(iBox.centerX(),
+                       iBox.y() - (0.5f + kVerticalSpacing) * accentSize,
+                       accentSize / 2,
+                       paint);
+
+    path.reset();
+    path.moveTo(iBox.centerX() - accentSize / 2, iBox.bottom() + kVerticalSpacing * accentSize);
+    path.rLineTo(accentSize, 0);
+    path.lineTo(iBox.centerX(), underlineY);
+    canvas->drawPath(path, paint);
+
+    SkRect underlineRect = SkRect::MakeLTRB(iBox.centerX() - iBox.width() * accentSize * 3,
+                                            underlineY,
+                                            iBox.centerX(),
+                                            underlineY + accentSize / 10);
+    const SkPoint pts1[] = { SkPoint::Make(underlineRect.x(), 0),
+                             SkPoint::Make(iBox.centerX(), 0) };
+    const SkScalar pos1[] = { 0, 0.75f };
+    const SkColor colors1[] = { SK_ColorTRANSPARENT, SK_ColorBLACK };
+    SkASSERT(SK_ARRAY_COUNT(pos1) == SK_ARRAY_COUNT(colors1));
+    SkAutoTUnref<SkShader> gradient1(SkGradientShader::CreateLinear(pts1, colors1, pos1,
+                                                                    SK_ARRAY_COUNT(pos1),
+                                                                    SkShader::kClamp_TileMode));
+    paint.setShader(gradient1.get());
+    canvas->drawRect(underlineRect, paint);
+
+    const SkPoint pts2[] = { SkPoint::Make(iBox.x() - iBox.width() * kGradientPad, 0),
+                             SkPoint::Make(iBox.right() + iBox.width() * kGradientPad, 0) };
+    const SkScalar pos2[] = { 0, .01f, 1.0f/3, 1.0f/3, 2.0f/3, 2.0f/3, .99f, 1 };
+    const SkColor colors2[] = {
+        SK_ColorBLACK,
+        0xffca5139,
+        0xffca5139,
+        0xff8dbd53,
+        0xff8dbd53,
+        0xff5460a5,
+        0xff5460a5,
+        SK_ColorBLACK
+    };
+    SkASSERT(SK_ARRAY_COUNT(pos2) == SK_ARRAY_COUNT(colors2));
+    SkAutoTUnref<SkShader> gradient2(SkGradientShader::CreateLinear(pts2, colors2, pos2,
+                                                                    SK_ARRAY_COUNT(pos2),
+                                                                    SkShader::kClamp_TileMode));
+    paint.setShader(gradient2.get());
+    canvas->drawText(kSkiaStr, textLen, 0, 0, paint);
+}
+
+}
+

[robertphillips, 2015/07/20 17:32:43]

// This really interesting GM exercises ...
In particular why are the scales and opacity interesting

?

[f(malita), 2015/07/20 20:13:38]

Done.

+class PictureGeneratorGM : public skiagm::GM {
+public:
+    PictureGeneratorGM() : fRect(SkRect::MakeWH(200, 100)) { }
+
+protected:
+    SkString onShortName() override {
+        return SkString("pictureimagegenerator");
+    }
+
+    SkISize onISize() override {
+        return SkISize::Make(1160, 860);
+    }
+
+    void onOnceBeforeDraw() override {
+        SkPictureRecorder recorder;

[robertphillips, 2015/07/20 17:32:43]

Can we make 'fRect' just be local to this method ?
Maybe define 200 & 100 to be kPictureWidth & kPictureHeight at class scope?

[f(malita), 2015/07/20 20:13:37]

Done.

+        SkCanvas* canvas = recorder.beginRecording(fRect);
+        draw_vector_logo(canvas, fRect);
+        fPicture.reset(recorder.endRecording());
+    }
+
+    void onDraw(SkCanvas* canvas) override {
+        const struct {
+            SkISize  size;
+            SkScalar scaleX, scaleY;
+            SkScalar opacity;
+        } configs[] = {
+            { SkISize::Make(200, 100), 1, 1, 1 },
+            { SkISize::Make(200, 200), 1, 1, 1 },
+            { SkISize::Make(200, 200), 1, 2, 1 },
+            { SkISize::Make(400, 200), 2, 2, 1 },
+
+            { SkISize::Make(200, 100), 1, 1, 0.9f  },
+            { SkISize::Make(200, 200), 1, 1, 0.75f },
+            { SkISize::Make(200, 200), 1, 2, 0.5f  },
+            { SkISize::Make(400, 200), 2, 2, 0.25f },
+
+            { SkISize::Make(200, 200), 0.5f, 1,    1 },
+            { SkISize::Make(200, 200), 1,    0.5f, 1 },
+            { SkISize::Make(200, 200), 0.5f, 0.5f, 1 },
+            { SkISize::Make(200, 200), 2,    2,    1 },
+
+            { SkISize::Make(200, 100), -1,  1, 1    },
+            { SkISize::Make(200, 100),  1, -1, 1    },
+            { SkISize::Make(200, 100), -1, -1, 1    },
+            { SkISize::Make(200, 100), -1, -1, 0.5f },
+        };
+
+        const unsigned kDrawsPerRow = 4;
+        const unsigned kDrawSize = 250;
+
+        for (size_t i = 0; i < SK_ARRAY_COUNT(configs); ++i) {
+            SkPaint p;
+            p.setAlpha(255 * configs[i].opacity);
+
+            SkMatrix m = SkMatrix::MakeScale(configs[i].scaleX, configs[i].scaleY);
+            if (configs[i].scaleX < 0) {
+                m.postTranslate(configs[i].size.width(), 0);
+            }
+            if (configs[i].scaleY < 0) {
+                m.postTranslate(0, configs[i].size.height());
+            }
+            SkAutoTDelete<SkImageGenerator> gen(
+                SkImageGenerator::NewFromPicture(configs[i].size, fPicture.get(), &m,
+                                                 p.getAlpha() != 255 ? &p : nullptr));
+            SkBitmap bm;
+            SkAssertResult(SkInstallDiscardablePixelRef(gen.detach(), &bm));
+
+            const SkScalar x = kDrawSize * (i % kDrawsPerRow);
+            const SkScalar y = kDrawSize * (i / kDrawsPerRow);
+
+            p.setColor(0xfff0f0f0);
+            p.setAlpha(255);
+            canvas->drawRect(SkRect::MakeXYWH(x, y, bm.width(), bm.height()), p);
+            canvas->drawBitmap(bm, x, y);
+        }
+    }
+
+private:
+    const SkRect            fRect;
+    SkAutoTUnref<SkPicture> fPicture;
+
+    typedef skiagm::GM INHERITED;
+};
+
+DEF_GM( return SkNEW(PictureGeneratorGM); )