bitmapscroll.cpp revision 36352bf5e38f45a70ee4f4fc132a38048d38206d 
1
2/*
3 * Copyright 2011 Google Inc.
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8#include "gm.h"
9
10namespace skiagm {
11
12/** Create a bitmap image suitable for testing SkBitmap::scrollRect().
13 *
14 *  @param quarterWidth bitmap will be 4x this many pixels wide
15 *  @param quarterHeight bitmap will be 4x this many pixels tall
16 *  @param bitmap the bitmap data is written into this object
17 */
18static void make_bitmap(int quarterWidth, int quarterHeight, SkBitmap *bitmap) {
19    SkPaint pRed, pWhite, pGreen, pBlue, pLine, pAlphaGray;
20    pRed.setColor(0xFFFF9999);
21    pWhite.setColor(0xFFFFFFFF);
22    pGreen.setColor(0xFF99FF99);
23    pBlue.setColor(0xFF9999FF);
24    pLine.setColor(0xFF000000);
25    pLine.setStyle(SkPaint::kStroke_Style);
26    pAlphaGray.setColor(0x66888888);
27
28    // Prepare bitmap, and a canvas that draws into it.
29    bitmap->allocN32Pixels(quarterWidth*4, quarterHeight*4);
30    SkCanvas canvas(*bitmap);
31
32    SkScalar w = SkIntToScalar(quarterWidth);
33    SkScalar h = SkIntToScalar(quarterHeight);
34    canvas.drawRectCoords(  0,   0, w*2, h*2, pRed);
35    canvas.drawRectCoords(w*2,   0, w*4, h*2, pGreen);
36    canvas.drawRectCoords(  0, h*2, w*2, h*4, pBlue);
37    canvas.drawRectCoords(w*2, h*2, w*4, h*4, pWhite);
38    canvas.drawRectCoords(w, h, w*3, h*3, pAlphaGray);
39    canvas.drawLine(w*2,   0, w*2, h*4, pLine);
40    canvas.drawLine(  0, h*2, w*4, h*2, pLine);
41    canvas.drawRectCoords(w, h, w*3, h*3, pLine);
42}
43
44class BitmapScrollGM : public GM {
45    bool fInited;
46    void init() {
47        if (fInited) {
48            return;
49        }
50        fInited = true;
51        // Create the original bitmap.
52        make_bitmap(quarterWidth, quarterHeight, &origBitmap);
53    }
54
55public:
56    BitmapScrollGM() {
57        fInited = false;
58        this->setBGColor(0xFFDDDDDD);
59    }
60
61protected:
62    SkString onShortName() override {
63        return SkString("bitmapscroll");
64    }
65
66    SkISize onISize() override {
67      return SkISize::Make(800, 600);
68    }
69
70    void onDraw(SkCanvas* canvas) override {
71        this->init();
72        SkIRect scrollCenterRegion = SkIRect::MakeXYWH(
73            quarterWidth, quarterHeight, quarterWidth*2+1, quarterHeight*2+1);
74        int x = quarterWidth;
75        int y = quarterHeight;
76        int xSpacing = quarterWidth * 20;
77        int ySpacing = quarterHeight * 16;
78
79        // Draw left-hand text labels.
80        drawLabel(canvas, "scroll entire bitmap",
81                  x, y, x, y + ySpacing);
82        drawLabel(canvas, "scroll part of bitmap",
83                  x, y + ySpacing, x, y + ySpacing*2);
84        x += 30;
85
86        // Draw various permutations of scrolled bitmaps, scrolling a bit
87        // further each time.
88        draw9(canvas, x, y, NULL, quarterWidth*1/2, quarterHeight*1/2);
89        draw9(canvas, x, y+ySpacing, &scrollCenterRegion,
90              quarterWidth*1/2, quarterHeight*1/2);
91        x += xSpacing;
92        draw9(canvas, x, y, NULL, quarterWidth*3/2, quarterHeight*3/2);
93        draw9(canvas, x, y+ySpacing, &scrollCenterRegion,
94              quarterWidth*3/2, quarterHeight*3/2);
95        x += xSpacing;
96        draw9(canvas, x, y, NULL, quarterWidth*5/2, quarterHeight*5/2);
97        draw9(canvas, x, y+ySpacing, &scrollCenterRegion,
98              quarterWidth*5/2, quarterHeight*5/2);
99        x += xSpacing;
100        draw9(canvas, x, y, NULL, quarterWidth*9/2, quarterHeight*9/2);
101        draw9(canvas, x, y+ySpacing, &scrollCenterRegion,
102              quarterWidth*9/2, quarterHeight*9/2);
103    }
104
105    void drawLabel(SkCanvas* canvas, const char *text, int startX, int startY,
106                 int endX, int endY) {
107        SkPaint paint;
108        sk_tool_utils::set_portable_typeface(&paint);
109        paint.setColor(0xFF000000);
110        SkPath path;
111        path.moveTo(SkIntToScalar(startX), SkIntToScalar(startY));
112        path.lineTo(SkIntToScalar(endX), SkIntToScalar(endY));
113        canvas->drawTextOnPath(text, strlen(text), path, NULL, paint);
114    }
115
116    /** Stamp out 9 copies of origBitmap, scrolled in each direction (and
117     *  not scrolled at all).
118     */
119    void draw9(SkCanvas* canvas, int x, int y, SkIRect* subset,
120               int scrollX, int scrollY) {
121        for (int yMult=-1; yMult<=1; yMult++) {
122            for (int xMult=-1; xMult<=1; xMult++) {
123                // Figure out the (x,y) to draw this copy at
124                SkScalar bitmapX = SkIntToScalar(
125                    x + quarterWidth * 5 * (xMult+1));
126                SkScalar bitmapY = SkIntToScalar(
127                    y + quarterHeight * 5 * (yMult+1));
128
129                // Scroll a new copy of the bitmap, and then draw it.
130                // scrollRect() should always return true, even if it's a no-op
131                SkBitmap scrolledBitmap;
132                SkDEBUGCODE(bool copyToReturnValue = )origBitmap.copyTo(
133                    &scrolledBitmap, origBitmap.colorType());
134                SkASSERT(copyToReturnValue);
135                SkDEBUGCODE(bool scrollRectReturnValue = )scrolledBitmap.scrollRect(
136                    subset, scrollX * xMult, scrollY * yMult);
137                SkASSERT(scrollRectReturnValue);
138                canvas->drawBitmap(scrolledBitmap, bitmapX, bitmapY);
139            }
140        }
141    }
142
143private:
144    typedef GM INHERITED;
145    static const int quarterWidth = 10;
146    static const int quarterHeight = 14;
147    SkBitmap origBitmap;
148};
149
150//////////////////////////////////////////////////////////////////////////////
151
152static GM* MyFactory(void*) { return new BitmapScrollGM; }
153static GMRegistry reg(MyFactory);
154
155}
156