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comparison foosdk/sdk/libPPUI/gdiplus-helpers-webp.h @ 1:20d02a178406 default tip

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*: check in everything else yay
author Paper <paper@tflc.us>
date Mon, 05 Jan 2026 02:15:46 -0500
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0:e9bb126753e7 1:20d02a178406
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 }