Skia深入分析3——skia图片绘制的实现(1)

<span style="font-size:14px;">#include "SkBitmapProcShader.h"
#include "SkCanvas.h"
#include "SkBitmap.h"
#include "SkImageDecoder.h"
#include "SkImageEncoder.h"
#include "SkRect.h"
int main()
{
    const int w = 1080;
    const int h = 1920;
    /*准备目标图片和源图片*/
    SkBitmap dst;
    dst.allocPixels(SkImageInfo::Make(w, h, kN32_SkColorType, kPremul_SkAlphaType));
    SkCanvas c(dst);

    SkBitmap src;
    SkImageDecoder::DecodeFile("test.jpg", &src);

    /*各种绘制图片方法使用示例*/
    {
        c.drawBitmap(src, 0, 0, NULL);
    }

    {
        c.drawSprite(src, 400, 400, NULL);
    }
    {
        SkRect dstR;
        r.set(29, 29, 100, 100);
        SkRect srcR;
        r.set(0,0,40,50);
        c.drawBitmapRectToRect(src, &srcR, dstR, NULL);
    }
    {
        SkMatrix m;
        m.setScale(1.4,4.3);
        c.drawBitmapMatrix(src, m, NULL);
    }
    {
        SkRect dstRect;
        dstRect.set(100,100,480,920);
        SkPaint paint;
        SkMatrix m;
        m.setScale(3.2, 4.1);
        SkShader* shader = CreateBitmapShader(src, SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode, m, NULL);
        paint.setShader(shader);
        SkSafeUnref(shader);
        c.drawRect(dstRect, paint);
    }

    /*输出图片*/
    SkImageEncoder::EncodeFile("output.jpg", dst, SkImageEncoder::kJPEG_Type, 100);
    return 1;
}</span>

2、流程解析