matriximagefilter.cpp

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/*
 * Copyright 2014 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
#include "gm/gm.h"
#include "include/core/SkBitmap.h"
#include "include/core/SkCanvas.h"
#include "include/core/SkColor.h"
#include "include/core/SkImage.h"
#include "include/core/SkMatrix.h"
#include "include/core/SkPaint.h"
#include "include/core/SkRect.h"
#include "include/core/SkScalar.h"
#include "include/effects/SkImageFilters.h"
 
static void draw(SkCanvas* canvas, const SkRect& rect, const SkBitmap& bitmap,
                 const SkMatrix& matrix, const SkSamplingOptions& sampling) {
        SkPaint paint;
        paint.setImageFilter(SkImageFilters::MatrixTransform(matrix, sampling, nullptr));
        canvas->saveLayer(&rect, &paint);
        canvas->drawImage(bitmap.asImage(), 0, 0, sampling);
        canvas->restore();
}
 
static void make_checkerboard(SkBitmap* bitmap) {
        bitmap->allocN32Pixels(64, 64);
        SkCanvas canvas(*bitmap);
        SkPaint darkPaint;
        darkPaint.setColor(0xFF404040);
        SkPaint lightPaint;
        lightPaint.setColor(0xFFA0A0A0);
        for (int y = 0; y < 64; y += 32) {
            for (int x = 0; x < 64; x += 32) {
                canvas.save();
                canvas.translate(SkIntToScalar(x), SkIntToScalar(y));
                canvas.drawRect(SkRect::MakeXYWH(0, 0, 16, 16), darkPaint);
                canvas.drawRect(SkRect::MakeXYWH(16, 0, 16, 16), lightPaint);
                canvas.drawRect(SkRect::MakeXYWH(0, 16, 16, 16), lightPaint);
                canvas.drawRect(SkRect::MakeXYWH(16, 16, 16, 16), darkPaint);
                canvas.restore();
            }
        }
}
 
DEF_SIMPLE_GM_BG(matriximagefilter, canvas, 420, 100, SK_ColorBLACK) {
        SkMatrix matrix;
        SkScalar margin = SkIntToScalar(10);
        matrix.setSkew(SkDoubleToScalar(0.5), SkDoubleToScalar(0.2));
        SkBitmap checkerboard;
        make_checkerboard(&checkerboard);
 
        SkRect srcRect = SkRect::MakeWH(96, 96);
 
        canvas->translate(margin, margin);
        draw(canvas, srcRect, checkerboard, matrix, SkSamplingOptions());
 
        canvas->translate(srcRect.width() + margin, 0);
        draw(canvas, srcRect, checkerboard, matrix, SkSamplingOptions(SkFilterMode::kLinear));
}