|
1
|
1 #pragma once
|
|
|
2
|
|
|
3 #include "gdiplus_helpers.h"
|
|
|
4
|
|
|
5 // Presumes prior #include of webp/decode.h
|
|
|
6
|
|
|
7 inline bool IsImageWebP(const void * ptr, size_t bytes) {
|
|
|
8 if (bytes < 12) return false;
|
|
|
9 return memcmp(ptr, "RIFF", 4) == 0 && memcmp((const char*)ptr + 8, "WEBP", 4) == 0;
|
|
|
10 }
|
|
|
11
|
|
|
12
|
|
|
13 // WebP-aware GdiplusImageFromMem
|
|
|
14 static std::unique_ptr<Gdiplus::Image> GdiplusImageFromMem2(const void * ptr, size_t bytes) {
|
|
|
15 GdiplusErrorHandler EH;
|
|
|
16 using namespace Gdiplus;
|
|
|
17 if (IsImageWebP(ptr, bytes)) {
|
|
|
18 WebPBitstreamFeatures bs;
|
|
|
19 if (WebPGetFeatures((const uint8_t*)ptr, bytes, &bs) != VP8_STATUS_OK) {
|
|
|
20 throw std::runtime_error("WebP decoding failure");
|
|
|
21 }
|
|
|
22 const Gdiplus::PixelFormat pf = bs.has_alpha ? PixelFormat32bppARGB : PixelFormat32bppRGB;
|
|
|
23 const int pfBytes = 4; // Gdiplus RGB is 4 bytes
|
|
|
24 int w = 0, h = 0;
|
|
|
25 // ALWAYS decode BGRA, Gdiplus will disregard alpha if was not originally present
|
|
|
26 uint8_t * decodedData = WebPDecodeBGRA((const uint8_t*)ptr, bytes, &w, &h);
|
|
|
27 pfc::onLeaving scope([decodedData] {WebPFree(decodedData); });
|
|
|
28 if (decodedData == nullptr || w <= 0 || h <= 0) throw std::runtime_error("WebP decoding failure");
|
|
|
29
|
|
|
30 std::unique_ptr<Bitmap> ret ( new Gdiplus::Bitmap(w, h, pf) );
|
|
|
31 EH << ret->GetLastStatus();
|
|
|
32 Rect rc(0, 0, w, h);
|
|
|
33 Gdiplus::BitmapData bitmapData;
|
|
|
34 EH << ret->LockBits(&rc, 0, pf, &bitmapData);
|
|
|
35 uint8_t * target = (uint8_t*)bitmapData.Scan0;
|
|
|
36 const uint8_t * source = decodedData;
|
|
|
37 for (int y = 0; y < h; ++y) {
|
|
|
38 memcpy(target, source, w * pfBytes);
|
|
|
39 target += bitmapData.Stride;
|
|
|
40 source += pfBytes * w;
|
|
|
41 }
|
|
|
42 EH << ret->UnlockBits(&bitmapData);
|
|
|
43 return ret;
|
|
|
44 }
|
|
|
45 return GdiplusImageFromMem(ptr, bytes);
|
|
|
46 }
|
