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->reset();
30    bitmap->setConfig(SkBitmap::kARGB_8888_Config,
31                      quarterWidth*4, quarterHeight*4);
32    bitmap->allocPixels();
33    SkCanvas canvas(*bitmap);
34
35    SkScalar w = SkIntToScalar(quarterWidth);
36    SkScalar h = SkIntToScalar(quarterHeight);
37    canvas.drawRectCoords(  0,   0, w*2, h*2, pRed);
38    canvas.drawRectCoords(w*2,   0, w*4, h*2, pGreen);
39    canvas.drawRectCoords(  0, h*2, w*2, h*4, pBlue);
40    canvas.drawRectCoords(w*2, h*2, w*4, h*4, pWhite);
41    canvas.drawRectCoords(w, h, w*3, h*3, pAlphaGray);
42    canvas.drawLine(w*2,   0, w*2, h*4, pLine);
43    canvas.drawLine(  0, h*2, w*4, h*2, pLine);
44    canvas.drawRectCoords(w, h, w*3, h*3, pLine);
45}
46
47class BitmapScrollGM : public GM {
48    bool fInited;
49    void init() {
50        if (fInited) {
51            return;
52        }
53        fInited = true;
54        // Create the original bitmap.
55        make_bitmap(quarterWidth, quarterHeight, &origBitmap);
56    }
57
58public:
59    BitmapScrollGM() {
60        fInited = false;
61        this->setBGColor(0xFFDDDDDD);
62    }
63
64protected:
65    virtual SkString onShortName() {
66        return SkString("bitmapscroll");
67    }
68
69    virtual SkISize onISize() {
70      return make_isize(800, 600);
71    }
72
73    virtual void onDraw(SkCanvas* canvas) {
74        this->init();
75        SkIRect scrollCenterRegion = SkIRect::MakeXYWH(
76            quarterWidth, quarterHeight, quarterWidth*2+1, quarterHeight*2+1);
77        int x = quarterWidth;
78        int y = quarterHeight;
79        int xSpacing = quarterWidth * 20;
80        int ySpacing = quarterHeight * 16;
81
82        // Draw left-hand text labels.
83        drawLabel(canvas, "scroll entire bitmap",
84                  x, y, x, y + ySpacing);
85        drawLabel(canvas, "scroll part of bitmap",
86                  x, y + ySpacing, x, y + ySpacing*2);
87        x += 30;
88
89        // Draw various permutations of scrolled bitmaps, scrolling a bit
90        // further each time.
91        draw9(canvas, x, y, NULL, quarterWidth*1/2, quarterHeight*1/2);
92        draw9(canvas, x, y+ySpacing, &scrollCenterRegion,
93              quarterWidth*1/2, quarterHeight*1/2);
94        x += xSpacing;
95        draw9(canvas, x, y, NULL, quarterWidth*3/2, quarterHeight*3/2);
96        draw9(canvas, x, y+ySpacing, &scrollCenterRegion,
97              quarterWidth*3/2, quarterHeight*3/2);
98        x += xSpacing;
99        draw9(canvas, x, y, NULL, quarterWidth*5/2, quarterHeight*5/2);
100        draw9(canvas, x, y+ySpacing, &scrollCenterRegion,
101              quarterWidth*5/2, quarterHeight*5/2);
102        x += xSpacing;
103        draw9(canvas, x, y, NULL, quarterWidth*9/2, quarterHeight*9/2);
104        draw9(canvas, x, y+ySpacing, &scrollCenterRegion,
105              quarterWidth*9/2, quarterHeight*9/2);
106    }
107
108    void drawLabel(SkCanvas* canvas, const char *text, int startX, int startY,
109                 int endX, int endY) {
110        SkPaint paint;
111        paint.setColor(0xFF000000);
112        SkPath path;
113        path.moveTo(SkIntToScalar(startX), SkIntToScalar(startY));
114        path.lineTo(SkIntToScalar(endX), SkIntToScalar(endY));
115        canvas->drawTextOnPath(text, strlen(text), path, NULL, paint);
116    }
117
118    /** Stamp out 9 copies of origBitmap, scrolled in each direction (and
119     *  not scrolled at all).
120     */
121    void draw9(SkCanvas* canvas, int x, int y, SkIRect* subset,
122               int scrollX, int scrollY) {
123        for (int yMult=-1; yMult<=1; yMult++) {
124            for (int xMult=-1; xMult<=1; xMult++) {
125                // Figure out the (x,y) to draw this copy at
126                SkScalar bitmapX = SkIntToScalar(
127                    x + quarterWidth * 5 * (xMult+1));
128                SkScalar bitmapY = SkIntToScalar(
129                    y + quarterHeight * 5 * (yMult+1));
130
131                // Scroll a new copy of the bitmap, and then draw it.
132                // scrollRect() should always return true, even if it's a no-op
133                SkBitmap scrolledBitmap;
134                SkDEBUGCODE(bool copyToReturnValue = )origBitmap.copyTo(
135                    &scrolledBitmap, origBitmap.config());
136                SkASSERT(copyToReturnValue);
137                SkDEBUGCODE(bool scrollRectReturnValue = )scrolledBitmap.scrollRect(
138                    subset, scrollX * xMult, scrollY * yMult);
139                SkASSERT(scrollRectReturnValue);
140                canvas->drawBitmap(scrolledBitmap, bitmapX, bitmapY);
141            }
142        }
143    }
144
145private:
146    typedef GM INHERITED;
147    static const int quarterWidth = 10;
148    static const int quarterHeight = 14;
149    SkBitmap origBitmap;
150};
151
152//////////////////////////////////////////////////////////////////////////////
153
154static GM* MyFactory(void*) { return new BitmapScrollGM; }
155static GMRegistry reg(MyFactory);
156
157}
158