parse icc profiles

src/core/SkColorSpace.cpp

Index: src/core/SkColorSpace.cpp
diff --git a/src/core/SkColorSpace.cpp b/src/core/SkColorSpace.cpp
index 6651abb3fca864086418a36be5bfb066e42dd3b0..5dfb9d8da59061929389c9eef92723c7e7d80c16 100644
--- a/src/core/SkColorSpace.cpp
+++ b/src/core/SkColorSpace.cpp
@@ -114,11 +114,13 @@ SkColorSpace* SkColorSpace::NewRGB(const SkFloat3x3& toXYZD50, const SkFloat3& g
         }
     }
 
+#if 0
     // check the matrix for invertibility
     float d = det(toXYZD50);
     if (!SkFloatIsFinite(d) || !SkFloatIsFinite(1 / d)) {
         return nullptr;
     }
+#endif
 
     return new SkColorSpace(toXYZD50, gamma, kUnknown_Named);
 }
@@ -157,6 +159,243 @@ SkColorSpace* SkColorSpace::NewNamed(Named named) {
 }
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
+#include "SkEndian.h"
+#include "SkStream.h"
+
+#define return_if_false(pred, msg) \
+    do { if (!(pred)) { SkDebugf("parsing icc profile: %s\n", msg); return false; } } while (0)
+
+#define return_null(msg)    do { SkDebugf("ICC Profile: %s\n", (msg)); return nullptr; } while (0)
+
+const uint32_t kRGB_ColorSpace   = SkSetFourByteTag('R', 'G', 'B', ' ');
+const uint32_t kGray_ColorSpace  = SkSetFourByteTag('G', 'R', 'A', 'Y');
+
+const uint32_t kTAG_rXYZ    = SkSetFourByteTag('r', 'X', 'Y', 'Z');
+const uint32_t kTAG_gXYZ    = SkSetFourByteTag('g', 'X', 'Y', 'Z');
+const uint32_t kTAG_bXYZ    = SkSetFourByteTag('b', 'X', 'Y', 'Z');
+
+const uint32_t kTAG_rTRC    = SkSetFourByteTag('r', 'T', 'R', 'C');
+const uint32_t kTAG_gTRC    = SkSetFourByteTag('g', 'T', 'R', 'C');
+const uint32_t kTAG_bTRC    = SkSetFourByteTag('b', 'T', 'R', 'C');
+
+struct ICCProfileHeader {
+    uint32_t    fSize;
+    uint32_t    fCMMType;
+    uint32_t    fVersion;
+    uint32_t    fClassProfile;
+    uint32_t    fColorSpace;
+    uint32_t    fPCS;
+    uint32_t    fCreated[3];
+    uint32_t    fSignature;
+    uint32_t    fPlatformTarget_ignored;
+    uint32_t    fFlags_ignored;
+    uint32_t    fManufacturer_ignored;
+    uint32_t    fDeviceModel_ignored;
+    uint32_t    fDeviceAttributes_ignored[2];
+    uint32_t    fRenderingIntent;
+    uint32_t    fIlluminantXYZ_ignored[3];
+    uint32_t    fCreator_ignored;
+
+    uint32_t    fReserved_ignored[11];
+
+    bool init(const uint32_t data[], size_t length) {
+        SkASSERT(128 == sizeof(*this));
+        if (length < 128) {
+            return false;
+        }
+        uint32_t* ptr = &fSize;
+        for (int i = 0; i < 32; ++i) {
+            ptr[i] = SkEndian_SwapBE32(data[i]);
+        }
+        return true;
+    }
+
+    bool valid() const {
+        return_if_false(fSize > 128, "size too small");
+
+        uint8_t version[4];
+        memcpy(version, &fVersion, sizeof(version));
+        return_if_false((version[3] == 2 || version[3] == 4) && version[0] == 0 && version[1] == 0,
+                        "unsupported version");
+        
+        const uint32_t kDisplay_Profile     = SkSetFourByteTag('m', 'n', 't', 'r');
+        const uint32_t kInput_Profile       = SkSetFourByteTag('s', 'c', 'n', 'r');
+        const uint32_t kOutput_Profile      = SkSetFourByteTag('p', 'r', 't', 'r');
+        return_if_false(fClassProfile == kDisplay_Profile ||
+                        fClassProfile == kInput_Profile ||
+                        fClassProfile == kOutput_Profile,
+                        "unsupported class profile");
+
+        return_if_false(fColorSpace == kRGB_ColorSpace ||
+                        fColorSpace == kGray_ColorSpace,
+                        "unsupported class profile");
+
+        const uint32_t kXYZ_PCSSpace    = SkSetFourByteTag('X', 'Y', 'Z', ' ');
+        return_if_false(fPCS == kXYZ_PCSSpace,
+                        "unsupported class profile");
+
+        return_if_false(fSignature == SkSetFourByteTag('a', 'c', 's', 'p'), "bad signature");
+
+        enum ICCIntents {
+            kPerceptual          = 0,
+            kRelativeColormetric = 1,
+            kSaturation          = 2,
+            kAbsoluteColorMetric = 3,
+        };
+        return_if_false(fRenderingIntent >= 0 || fRenderingIntent <= 3, "bad rendering intent");
+        
+        return true;
+    }
+};
+
+struct ICCTag {
+    uint32_t    fSignature;
+    uint32_t    fOffset;
+    uint32_t    fLength;
+
+    const uint32_t* init(const uint32_t data[]) {
+        fSignature = SkEndian_SwapBE32(data[0]);
+        fOffset = SkEndian_SwapBE32(data[1]);
+        fLength = SkEndian_SwapBE32(data[2]);
+        return data + 3;
+    }
+
+    const uint32_t* addr(const uint32_t* base) const {
+        SkASSERT(SkIsAlign4(fOffset));
+        return base + (fOffset >> 2);
+    }
+
+    static const ICCTag* Find(const ICCTag tags[], int count, uint32_t signature) {
+        for (int i = 0; i < count; ++i) {
+            if (tags[i].fSignature == signature) {
+                return &tags[i];
+            }
+        }
+        return nullptr;
+    }
+};
+
+void load_3x(float dst[3], const uint32_t data[]) {
+    uint32_t tag = SkEndian_SwapBE32(data[0]);
+    dst[0] = SkFixedToFloat(SkEndian_SwapBE32(data[2]));
+    dst[1] = SkFixedToFloat(SkEndian_SwapBE32(data[2]));
+    dst[2] = SkFixedToFloat(SkEndian_SwapBE32(data[2]));
+    SkDebugf("3x tag %08X %g %g %g\n", tag, dst[0], dst[1], dst[2]);
+}
+
+const uint32_t kTAG_CurveType   = SkSetFourByteTag('c', 'u', 'r', 'v');
+const uint32_t kTAG_ParaCurveType   = SkSetFourByteTag('p', 'a', 'r', 'a');
+
+static float load_gamma(const uint32_t data[]) {
+    uint32_t type = SkEndian_SwapBE32(data[0]);
+    switch (type) {
+        case kTAG_CurveType: {
+            int count = SkEndian_SwapBE32(data[2]);
+            const uint16_t* table = (const uint16_t*)&data[3];
+            if (1 == count) {   // table entry is the exponent (bias 256)
+                unsigned value = SkEndian_SwapBE16(table[0]);
+                float gamma = value / 256.0f;
+                SkDebugf("gamma %d %g\n", value, gamma);
+                return gamma;
+            }
+            // general interp table (ingored for now)
+            for (int i = 0; i < count; ++i) {
+                unsigned value = SkEndian_SwapBE16(table[i]);
+                SkDebugf("curve[%d] %d\n", i, value);
+            }
+            return 2.2f;
+        } break;
+        case kTAG_ParaCurveType: {
+            SkDebugf("parametric curve\n");
+            return 2.2f;
+        } break;
+        default:
+            return 1;
+    }
+}
+
+SkColorSpace* SkColorSpace::NewICCProfile32(const uint32_t base[], size_t length) {
+    const uint32_t storedSize = SkEndian_SwapBE32(base[0]);
+    if (storedSize < 128+4) {
+        return nullptr; // too small
+    }
+    if (length > storedSize) {
+        length = storedSize;
+    }
+
+    ICCProfileHeader header;
+    if (!header.init(base, length) || !header.valid()) {
+        return nullptr;
+    }
+
+    const uint32_t* data = base + (128/4);
+    int tagCount = SkEndian_SwapBE32(*data++);
+    if (tagCount < 0 || tagCount > 100) {
+        return nullptr;
+    }
+
+    SkDebugf("%d tags\n", tagCount);
+    SkAutoTArray<ICCTag> tags(tagCount);
+    for (int i = 0; i < tagCount; ++i) {
+        data = tags[i].init(data);
+        SkDebugf("[%d] %c%c%c%c %d %d\n", i,
+                 (tags[i].fSignature >> 24) & 0xFF, (tags[i].fSignature >> 16) & 0xFF,
+                 (tags[i].fSignature >>  8) & 0xFF, (tags[i].fSignature >>  0) & 0xFF,
+                 tags[i].fOffset, tags[i].fLength);
+    }
+
+    SkFloat3x3 toXYZ;
+    SkFloat3 gamma {{ 1, 1, 1 }};
+
+    // Load up our matrix
+    switch (header.fColorSpace) {
+        case kRGB_ColorSpace: {
+            const ICCTag* r = ICCTag::Find(tags.get(), tagCount, kTAG_rXYZ);
+            const ICCTag* g = ICCTag::Find(tags.get(), tagCount, kTAG_gXYZ);
+            const ICCTag* b = ICCTag::Find(tags.get(), tagCount, kTAG_bXYZ);
+            if (!r || !g || !b) {
+                return_null("needed rgb tags for XYZ space");
+            }
+            load_3x(&toXYZ.fMat[0], r->addr(base));
+            load_3x(&toXYZ.fMat[3], g->addr(base));
+            load_3x(&toXYZ.fMat[6], b->addr(base));
+            
+            r = ICCTag::Find(tags.get(), tagCount, kTAG_rTRC);
+            g = ICCTag::Find(tags.get(), tagCount, kTAG_gTRC);
+            b = ICCTag::Find(tags.get(), tagCount, kTAG_bTRC);
+            if (r) {
+                gamma.fVec[0] = load_gamma(r->addr(base));
+            }
+            if (g) {
+                gamma.fVec[1] = load_gamma(g->addr(base));
+            }
+            if (b) {
+                gamma.fVec[2] = load_gamma(b->addr(base));
+            }
+            return SkColorSpace::NewRGB(toXYZ, gamma);
+        }
+        default:
+            break;
+    }
+    return_null("unsupported colorspace");
+}
+
+SkColorSpace* SkColorSpace::NewICCProfile(const void* ptr, size_t length) {
+    const uint32_t* data;
+    SkAutoTArray<uint32_t> storage;
+
+    if ((intptr_t)ptr & 3) {   // not 4-byte aligned
+        storage.reset(SkAlign4(length) >> 2);
+        memcpy(storage.get(), ptr, length);
+        data = storage.get();
+    } else {
+        data = (const uint32_t*)ptr;
+    }
+    return NewICCProfile32(data, length);
+}
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+///////////////////////////////////////////////////////////////////////////////////////////////////
 
 SkColorSpace::Result SkColorSpace::Concat(const SkColorSpace* src, const SkColorSpace* dst,
                                           SkFloat3x3* result) {