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      1 
      2 #include "SkTestImageFilters.h"
      3 #include "SkCanvas.h"
      4 #include "SkDevice.h"
      5 #include "SkReadBuffer.h"
      6 #include "SkWriteBuffer.h"
      7 
      8 // Simple helper canvas that "takes ownership" of the provided device, so that
      9 // when this canvas goes out of scope, so will its device. Could be replaced
     10 // with the following:
     11 //
     12 //  SkCanvas canvas(device);
     13 //  SkAutoTUnref<SkBaseDevice> aur(device);
     14 //
     15 class OwnDeviceCanvas : public SkCanvas {
     16 public:
     17     OwnDeviceCanvas(SkBaseDevice* device) : SkCanvas(device) {
     18         SkSafeUnref(device);
     19     }
     20 };
     21 
     22 ///////////////////////////////////////////////////////////////////////////////
     23 
     24 bool SkDownSampleImageFilter::onFilterImage(Proxy* proxy, const SkBitmap& src,
     25                                             const Context&,
     26                                             SkBitmap* result, SkIPoint*) const {
     27     SkScalar scale = fScale;
     28     if (scale > SK_Scalar1 || scale <= 0) {
     29         return false;
     30     }
     31 
     32     int dstW = SkScalarRoundToInt(src.width() * scale);
     33     int dstH = SkScalarRoundToInt(src.height() * scale);
     34     if (dstW < 1) {
     35         dstW = 1;
     36     }
     37     if (dstH < 1) {
     38         dstH = 1;
     39     }
     40 
     41     SkBitmap tmp;
     42 
     43     // downsample
     44     {
     45         SkBaseDevice* dev = proxy->createDevice(dstW, dstH);
     46         if (NULL == dev) {
     47             return false;
     48         }
     49         OwnDeviceCanvas canvas(dev);
     50         SkPaint paint;
     51 
     52         paint.setFilterLevel(SkPaint::kLow_FilterLevel);
     53         canvas.scale(scale, scale);
     54         canvas.drawBitmap(src, 0, 0, &paint);
     55         tmp = dev->accessBitmap(false);
     56     }
     57 
     58     // upscale
     59     {
     60         SkBaseDevice* dev = proxy->createDevice(src.width(), src.height());
     61         if (NULL == dev) {
     62             return false;
     63         }
     64         OwnDeviceCanvas canvas(dev);
     65 
     66         SkRect r = SkRect::MakeWH(SkIntToScalar(src.width()),
     67                                   SkIntToScalar(src.height()));
     68         canvas.drawBitmapRect(tmp, NULL, r, NULL);
     69         *result = dev->accessBitmap(false);
     70     }
     71     return true;
     72 }
     73 
     74 void SkDownSampleImageFilter::flatten(SkWriteBuffer& buffer) const {
     75     this->INHERITED::flatten(buffer);
     76 
     77     buffer.writeScalar(fScale);
     78 }
     79 
     80 SkDownSampleImageFilter::SkDownSampleImageFilter(SkReadBuffer& buffer)
     81   : INHERITED(1, buffer) {
     82     fScale = buffer.readScalar();
     83     buffer.validate(SkScalarIsFinite(fScale));
     84 }
     85