Experimental: EXR

src/codec/SkExrCodec.cpp

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkExrCodec.h"
+
+//#define TINYEXR_IMPLEMENTATION
+#include "tinyexr.h"
+
+bool SkExrCodec::IsExr(const void* buffer, size_t bytes) {
+    static constexpr uint8_t kExrSig[] = { 0x76, 0x2f, 0x31, 0x01, };
+    return bytes >= 4 && 0 == memcmp(buffer, kExrSig, 4);
+}
+
+SkCodec* SkExrCodec::NewFromStream(SkStream* stream) {
+    sk_sp<SkData> data = ((SkMemoryStream*) stream)->asData();
+
+    EXRVersion version;
+    int result = ParseEXRVersionFromMemory(&version, data->bytes(), data->size());
+    if (result != TINYEXR_SUCCESS) {
+      return nullptr;
+    }
+
+    EXRHeader header;
+    InitEXRHeader(&header);
+    result = ParseEXRHeaderFromMemory(&header, &version, data->bytes(), data->size(), nullptr);
+    if (TINYEXR_SUCCESS != result) {
+        return nullptr;
+    }
+
+    int width = header.data_window[2] - header.data_window[0] + 1;
+    int height = header.data_window[3] - header.data_window[1] + 1;
+    SkEncodedInfo info = SkEncodedInfo::Make(SkEncodedInfo::kRGB_Color,
+                                             SkEncodedInfo::kOpaque_Alpha, 8);
+    return new SkExrCodec(width, height, info, SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named),
+                          stream, data);
+}
+
+SkCodec::Result SkExrCodec::onGetPixels(const SkImageInfo& dstInfo, void* dst, size_t rowBytes,
+                                        const Options& options, SkPMColor*, int*,
+                                        int* rowsDecodedPtr) {
+    EXRVersion exr_version;
+    EXRImage exr_image;
+    EXRHeader exr_header;
+
+    InitEXRHeader(&exr_header);
+
+    int ret = ParseEXRVersionFromMemory(&exr_version, fData->bytes(), fData->size());
+    if (ret != TINYEXR_SUCCESS) {
+        return kInvalidInput;
+    }
+
+    ret = ParseEXRHeaderFromMemory(&exr_header, &exr_version, fData->bytes(), fData->size(), nullptr);
+    if (ret != TINYEXR_SUCCESS) {
+        return kInvalidInput;
+    }
+
+    int pixelTypes[] = {
+        TINYEXR_PIXELTYPE_FLOAT,
+        TINYEXR_PIXELTYPE_FLOAT,
+        TINYEXR_PIXELTYPE_FLOAT,
+        TINYEXR_PIXELTYPE_FLOAT,
+    };
+    exr_header.requested_pixel_types = pixelTypes;
+
+    InitEXRImage(&exr_image);
+    ret = LoadEXRImageFromMemory(&exr_image, &exr_header, fData->bytes(), nullptr);
+    if (ret != TINYEXR_SUCCESS) {
+        return kInvalidInput;
+    }
+
+    // RGBA
+    int idxR = -1;
+    int idxG = -1;
+    int idxB = -1;
+    for (int c = 0; c < exr_header.num_channels; c++) {
+        if (strcmp(exr_header.channels[c].name, "R") == 0) {
+            idxR = c;
+        } else if (strcmp(exr_header.channels[c].name, "G") == 0) {
+            idxG = c;
+        } else if (strcmp(exr_header.channels[c].name, "B") == 0) {
+            idxB = c;
+        }
+    }
+
+    if (idxR == -1 || idxG == -1 || idxB == -1) {
+        return kInvalidInput;
+    }
+
+    // Assume `out_rgba` have enough memory allocated.
+    uint32_t* dst32 = (uint32_t*) dst;
+    for (int i = 0; i < exr_image.width * exr_image.height; i++) {
+        SkColor4f rgba;
+        rgba.fR = reinterpret_cast<float **>(exr_image.images)[idxR][i];
+        rgba.fG = reinterpret_cast<float **>(exr_image.images)[idxG][i];
+        rgba.fB = reinterpret_cast<float **>(exr_image.images)[idxB][i];
+        rgba.fA = 1.0;
+        //SkDebugf("%g %g %g %g\n", rgba.fR, rgba.fG, rgba.fB, rgba.fA);
+        SkColor color = rgba.toSkColor();
+        dst32[i] = color;
+    }
+
+    return kSuccess;
+}
+
+SkExrCodec::SkExrCodec(int width, int height, const SkEncodedInfo& info,
+                       sk_sp<SkColorSpace> colorSpace, SkStream* stream, sk_sp<SkData> data)
+    : INHERITED(width, height, info, stream, std::move(colorSpace))
+    , fData(data)
+{}