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:
OwnDeviceCanvas(SkBaseDevice * device)17 OwnDeviceCanvas(SkBaseDevice* device) : SkCanvas(device) {
18 SkSafeUnref(device);
19 }
20 };
21
22 ///////////////////////////////////////////////////////////////////////////////
23
onFilterImage(Proxy * proxy,const SkBitmap & src,const Context &,SkBitmap * result,SkIPoint *) const24 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.setFilterQuality(kLow_SkFilterQuality);
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
CreateProc(SkReadBuffer & buffer)74 SkFlattenable* SkDownSampleImageFilter::CreateProc(SkReadBuffer& buffer) {
75 SK_IMAGEFILTER_UNFLATTEN_COMMON(common, 1);
76 return Create(buffer.readScalar(), common.getInput(0));
77 }
78
flatten(SkWriteBuffer & buffer) const79 void SkDownSampleImageFilter::flatten(SkWriteBuffer& buffer) const {
80 this->INHERITED::flatten(buffer);
81 buffer.writeScalar(fScale);
82 }
83
84 #ifndef SK_IGNORE_TO_STRING
toString(SkString * str) const85 void SkDownSampleImageFilter::toString(SkString* str) const {
86 str->appendf("SkDownSampleImageFilter: (");
87 str->append(")");
88 }
89 #endif
90