gm/modecolorfilters.cpp

/*
 * Copyright 2012 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 "SkBitmapProcShader.h"
#include "SkColorFilter.h"
#include "SkGradientShader.h"

#define WIDTH 512
#define HEIGHT 1024

namespace skiagm {

// Using gradients because GPU doesn't currently have an implementation of SkColorShader (duh!)
static SkShader* make_color_shader(SkColor color) {
    static const SkPoint kPts[] = {{0, 0}, {1, 1}};
    SkColor colors[] = {color, color};

    return SkGradientShader::CreateLinear(kPts, colors, NULL, 2, SkShader::kClamp_TileMode);
}

static SkShader* make_solid_shader() {
    return make_color_shader(SkColorSetARGB(0xFF, 0x40, 0x80, 0x20));
}

static SkShader* make_transparent_shader() {
    return make_color_shader(SkColorSetARGB(0x80, 0x10, 0x70, 0x20));
}

static SkShader* make_trans_black_shader() {
    return make_color_shader(0x0);
}

// draws a background behind each test rect to see transparency
static SkShader* make_bg_shader(int checkSize) {
    SkBitmap bmp;
    bmp.setConfig(SkBitmap::kARGB_8888_Config, 2 * checkSize, 2 * checkSize);
    bmp.allocPixels();
    SkCanvas canvas(bmp);
    canvas.clear(0xFF800000);
    SkPaint paint;
    paint.setColor(0xFF000080);
    SkRect rect0 = SkRect::MakeXYWH(0, 0,
                                    SkIntToScalar(checkSize), SkIntToScalar(checkSize));
    SkRect rect1 = SkRect::MakeXYWH(SkIntToScalar(checkSize), SkIntToScalar(checkSize),
                                    SkIntToScalar(checkSize), SkIntToScalar(checkSize));
    canvas.drawRect(rect1, paint);
    canvas.drawRect(rect0, paint);
    return SkNEW_ARGS(SkBitmapProcShader, (bmp, SkShader::kRepeat_TileMode,
                                                SkShader::kRepeat_TileMode));
}

class ModeColorFilterGM : public GM {
public:
    ModeColorFilterGM() {
        this->setBGColor(0xFF303030);
    }

protected:
    virtual SkString onShortName() {
        return SkString("modecolorfilters");
    }

    virtual SkISize onISize() {
        return make_isize(WIDTH, HEIGHT);
    }

    virtual void onDraw(SkCanvas* canvas) {
        // size of rect for each test case
        static const int kRectWidth  = 20;
        static const int kRectHeight = 20;        

        static const int kCheckSize  = 10;

        if (!fBmpShader) {
            fBmpShader.reset(make_bg_shader(kCheckSize));
        }
        SkPaint bgPaint;
        bgPaint.setShader(fBmpShader);
        bgPaint.setXfermodeMode(SkXfermode::kSrc_Mode);

        SkShader* shaders[] = {
            NULL,                                   // use a paint color instead of a shader
            make_solid_shader(),
            make_transparent_shader(),
            make_trans_black_shader(),
        };

        // used without shader
        SkColor colors[] = {
            SkColorSetARGB(0xFF, 0xFF, 0xFF, 0xFF),
            SkColorSetARGB(0xFF, 0x00, 0x00, 0x00),
            SkColorSetARGB(0x00, 0x00, 0x00, 0x00),
            SkColorSetARGB(0xFF, 0x10, 0x20, 0x40),
            SkColorSetARGB(0xA0, 0x20, 0x30, 0x90),
        };

        // used with shaders
        SkColor alphas[] = {0xFFFFFFFF, 0x80808080};
        
        SkXfermode::Mode modes[]  = { // currently just doing the Modes expressible as Coeffs
            SkXfermode::kClear_Mode,
            SkXfermode::kSrc_Mode,
            SkXfermode::kDst_Mode,
            SkXfermode::kSrcOver_Mode,
            SkXfermode::kDstOver_Mode,
            SkXfermode::kSrcIn_Mode,
            SkXfermode::kDstIn_Mode,
            SkXfermode::kSrcOut_Mode,
            SkXfermode::kDstOut_Mode,
            SkXfermode::kSrcATop_Mode,
            SkXfermode::kDstATop_Mode,
            SkXfermode::kXor_Mode,
            SkXfermode::kPlus_Mode,
            SkXfermode::kMultiply_Mode,
        };

        SkPaint paint;
        int idx = 0;
        static const int kRectsPerRow = SkMax32(this->getISize().fWidth / kRectWidth, 1);
        for (size_t cfm = 0; cfm < SK_ARRAY_COUNT(modes); ++cfm) {
            for (int cfc = 0; cfc < SK_ARRAY_COUNT(colors); ++cfc) {
                SkAutoTUnref<SkColorFilter> cf(SkColorFilter::CreateModeFilter(colors[cfc],
                                                                               modes[cfm]));
                paint.setColorFilter(cf);
                for (int s = 0; s < SK_ARRAY_COUNT(shaders); ++s) {
                    paint.setShader(shaders[s]);
                    bool hasShader = NULL == paint.getShader();
                    int paintColorCnt = hasShader ? SK_ARRAY_COUNT(alphas) : SK_ARRAY_COUNT(colors);
                    SkColor* paintColors = hasShader ? alphas : colors;
                    for (int pc = 0; pc < paintColorCnt; ++pc) {
                        paint.setColor(paintColors[pc]);
                        SkScalar x = SkIntToScalar(idx % kRectsPerRow);
                        SkScalar y = SkIntToScalar(idx / kRectsPerRow);
                        SkRect rect = SkRect::MakeXYWH(x * kRectWidth, y * kRectHeight,
                                                       kRectWidth, kRectHeight);
                        canvas->drawRect(rect, bgPaint);
                        canvas->drawRect(rect, paint);
                        ++idx;
                    }
                }
            }
        }

        for (int i = 0; i < SK_ARRAY_COUNT(shaders); ++i) {
            SkSafeUnref(shaders[i]);
        }
    }

private:
    SkAutoTUnref<SkShader> fBmpShader;
    typedef GM INHERITED;
};

//////////////////////////////////////////////////////////////////////////////

static GM* MyFactory(void*) { return new ModeColorFilterGM; }
static GMRegistry reg(MyFactory);

}