Add SkICC::rawTransferFnData()
BUG=skia:
Change-Id: I912b044a0091a4d396c954d1ad1d84f5f8d50f56
Reviewed-on: https://skia-review.googlesource.com/7366
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Matt Sarett <msarett@google.com>
diff --git a/gm/gradients.cpp b/gm/gradients.cpp
index 8ae1dd7..b909b50 100644
--- a/gm/gradients.cpp
+++ b/gm/gradients.cpp
@@ -170,7 +170,7 @@
class GradientsGM : public GM {
public:
GradientsGM(bool dither) : fDither(dither) {
- this->setBGColor(sk_tool_utils::color_to_565(0xFFDDDDDD));
+ //this->setBGColor(sk_tool_utils::color_to_565(0xFFDDDDDD));
}
protected:
@@ -185,10 +185,10 @@
SkPoint pts[2] = {
{ 0, 0 },
- { SkIntToScalar(100), SkIntToScalar(100) }
+ { SkIntToScalar(500), SkIntToScalar(500) }
};
SkShader::TileMode tm = SkShader::kClamp_TileMode;
- SkRect r = { 0, 0, SkIntToScalar(100), SkIntToScalar(100) };
+ SkRect r = { 0, 0, SkIntToScalar(500), SkIntToScalar(500) };
SkPaint paint;
paint.setAntiAlias(true);
paint.setDither(fDither);
@@ -207,8 +207,10 @@
paint.setShader(gGradMakers[j](pts, gGradData[i], tm, scale));
canvas->drawRect(r, paint);
canvas->translate(0, SkIntToScalar(120));
+ break;
}
canvas->restore();
+ break;
canvas->translate(SkIntToScalar(120), 0);
}
}
diff --git a/include/core/SkICC.h b/include/core/SkICC.h
index 3780498..04fa1da 100644
--- a/include/core/SkICC.h
+++ b/include/core/SkICC.h
@@ -8,6 +8,7 @@
#ifndef SkICC_DEFINED
#define SkICC_DEFINED
+#include "SkData.h"
#include "SkRefCnt.h"
struct SkColorSpaceTransferFn;
@@ -48,16 +49,48 @@
bool isNumericalTransferFn(SkColorSpaceTransferFn* fn) const;
/**
- * If the transfer function can be approximated as coefficients to the standard
- * equation, returns true and sets |fn| to the proper values.
+ * Please do not call this unless isNumericalTransferFn() has been called and it
+ * fails. SkColorSpaceTransferFn is the preferred representation.
*
- * If not, returns false. This indicates one of the following:
- * (1) The R, G, and B transfer functions are not the same.
- * (2) The transfer function is represented as a table that is not increasing with
- * end points at zero and one.
- * (3) The ICC data is too complex to isolate a single transfer function.
+ * If it is not possible to represent the R, G, and B transfer functions numerically
+ * and it is still necessary to get the transfer function, this will return the
+ * transfer functions as three tables (R, G, and B).
+ *
+ * If possible, this will return tables of the same length as they were specified in
+ * the ICC profile. This means that the lengths of the three tables are not
+ * guaranteed to be the same. If the ICC representation was not a table, the length
+ * will be chosen arbitrarily.
+ *
+ * Entries in the tables are guaranteed to be in [0, 1].
+ *
+ * This API may be deleted in favor of a numerical approximation of the raw data.
+ *
+ * This function may fail, indicating that the ICC profile does not have transfer
+ * functions.
*/
- bool approximateNumericalTransferFn(SkColorSpaceTransferFn* fn) const;
+ struct Channel {
+ // Byte offset of the start of the table in |fStorage|
+ size_t fOffset;
+ int fCount;
+ };
+ struct Tables {
+ Channel fRed;
+ Channel fGreen;
+ Channel fBlue;
+
+ const float* red() {
+ return (const float*) (fStorage->bytes() + fRed.fOffset);
+ }
+ const float* green() {
+ return (const float*) (fStorage->bytes() + fGreen.fOffset);
+ }
+ const float* blue() {
+ return (const float*) (fStorage->bytes() + fBlue.fOffset);
+ }
+
+ sk_sp<SkData> fStorage;
+ };
+ bool rawTransferFnData(Tables* tables) const;
/**
* Write an ICC profile with transfer function |fn| and gamut |toXYZD50|.
@@ -68,6 +101,8 @@
SkICC(sk_sp<SkColorSpace> colorSpace);
sk_sp<SkColorSpace> fColorSpace;
+
+ friend class ICCTest;
};
#endif
diff --git a/src/core/SkColorSpaceXformPriv.h b/src/core/SkColorSpaceXformPriv.h
index 5a2bb97..1f55891 100644
--- a/src/core/SkColorSpaceXformPriv.h
+++ b/src/core/SkColorSpaceXformPriv.h
@@ -9,6 +9,7 @@
#define SkColorSpaceXformPriv_DEFINED
#include "SkColorSpace_Base.h"
+#include "SkColorSpaceXform.h"
#include "SkHalf.h"
#include "SkSRGB.h"
diff --git a/src/core/SkICC.cpp b/src/core/SkICC.cpp
index 6b09f29..40a733f 100644
--- a/src/core/SkICC.cpp
+++ b/src/core/SkICC.cpp
@@ -9,6 +9,7 @@
#include "SkColorSpace_Base.h"
#include "SkColorSpace_XYZ.h"
#include "SkColorSpacePriv.h"
+#include "SkColorSpaceXformPriv.h"
#include "SkEndian.h"
#include "SkFixed.h"
#include "SkICC.h"
@@ -41,6 +42,101 @@
return as_CSB(fColorSpace)->onIsNumericalTransferFn(coeffs);
}
+static const int kDefaultTableSize = 512; // Arbitrary
+
+void fn_to_table(float* tablePtr, const SkColorSpaceTransferFn& fn) {
+ // Y = (aX + b)^g + e for X >= d
+ // Y = cX + f otherwise
+ for (int i = 0; i < kDefaultTableSize; i++) {
+ float x = ((float) i) / ((float) (kDefaultTableSize - 1));
+ if (x >= fn.fD) {
+ tablePtr[i] = clamp_0_1(powf(fn.fA * x + fn.fB, fn.fG) + fn.fE);
+ } else {
+ tablePtr[i] = clamp_0_1(fn.fC * x + fn.fF);
+ }
+ }
+}
+
+void copy_to_table(float* tablePtr, const SkGammas* gammas, int index) {
+ SkASSERT(gammas->isTable(index));
+ const float* ptr = gammas->table(index);
+ const size_t bytes = gammas->tableSize(index) * sizeof(float);
+ memcpy(tablePtr, ptr, bytes);
+}
+
+bool SkICC::rawTransferFnData(Tables* tables) const {
+ if (SkColorSpace_Base::Type::kA2B == as_CSB(fColorSpace)->type()) {
+ return false;
+ }
+ SkColorSpace_XYZ* colorSpace = (SkColorSpace_XYZ*) fColorSpace.get();
+
+ SkColorSpaceTransferFn fn;
+ if (this->isNumericalTransferFn(&fn)) {
+ tables->fStorage = SkData::MakeUninitialized(kDefaultTableSize * sizeof(float));
+ fn_to_table((float*) tables->fStorage->writable_data(), fn);
+ tables->fRed.fOffset = tables->fGreen.fOffset = tables->fBlue.fOffset = 0;
+ tables->fRed.fCount = tables->fGreen.fCount = tables->fBlue.fCount = kDefaultTableSize;
+ return true;
+ }
+
+ const SkGammas* gammas = colorSpace->gammas();
+ SkASSERT(gammas);
+ if (gammas->data(0) == gammas->data(1) && gammas->data(0) == gammas->data(2)) {
+ SkASSERT(gammas->isTable(0));
+ tables->fStorage = SkData::MakeUninitialized(gammas->tableSize(0) * sizeof(float));
+ copy_to_table((float*) tables->fStorage->writable_data(), gammas, 0);
+ tables->fRed.fOffset = tables->fGreen.fOffset = tables->fBlue.fOffset = 0;
+ tables->fRed.fCount = tables->fGreen.fCount = tables->fBlue.fCount = gammas->tableSize(0);
+ return true;
+ }
+
+ // Determine the storage size.
+ size_t storageSize = 0;
+ for (int i = 0; i < 3; i++) {
+ if (gammas->isTable(i)) {
+ storageSize += gammas->tableSize(i) * sizeof(float);
+ } else {
+ storageSize += kDefaultTableSize * sizeof(float);
+ }
+ }
+
+ // Fill in the tables.
+ tables->fStorage = SkData::MakeUninitialized(storageSize);
+ float* ptr = (float*) tables->fStorage->writable_data();
+ size_t offset = 0;
+ Channel rgb[3];
+ for (int i = 0; i < 3; i++) {
+ if (gammas->isTable(i)) {
+ copy_to_table(ptr, gammas, i);
+ rgb[i].fOffset = offset;
+ rgb[i].fCount = gammas->tableSize(i);
+ offset += rgb[i].fCount * sizeof(float);
+ ptr += rgb[i].fCount;
+ continue;
+ }
+
+ if (gammas->isNamed(i)) {
+ SkAssertResult(named_to_parametric(&fn, gammas->data(i).fNamed));
+ } else if (gammas->isValue(i)) {
+ value_to_parametric(&fn, gammas->data(i).fValue);
+ } else {
+ SkASSERT(gammas->isParametric(i));
+ fn = gammas->params(i);
+ }
+
+ fn_to_table(ptr, fn);
+ rgb[i].fOffset = offset;
+ rgb[i].fCount = kDefaultTableSize;
+ offset += kDefaultTableSize * sizeof(float);
+ ptr += kDefaultTableSize;
+ }
+
+ tables->fRed = rgb[0];
+ tables->fGreen = rgb[1];
+ tables->fBlue = rgb[2];
+ return true;
+}
+
///////////////////////////////////////////////////////////////////////////////////////////////////
// Google Skia (UTF-16)
diff --git a/tests/ICCTest.cpp b/tests/ICCTest.cpp
index 4bc296d..794483c 100644
--- a/tests/ICCTest.cpp
+++ b/tests/ICCTest.cpp
@@ -8,6 +8,7 @@
#include "Resources.h"
#include "SkColorSpace.h"
#include "SkColorSpacePriv.h"
+#include "SkColorSpace_XYZ.h"
#include "SkData.h"
#include "SkICC.h"
#include "SkMatrix44.h"
@@ -138,3 +139,153 @@
test_write_icc(r, srgbFn, srgbMatrix, SkColorSpace::MakeNamed(SkColorSpace::kSRGB_Named).get(),
false);
}
+
+static inline void test_raw_transfer_fn(skiatest::Reporter* r, SkICC* icc) {
+ SkICC::Tables tables;
+ bool result = icc->rawTransferFnData(&tables);
+ REPORTER_ASSERT(r, result);
+
+ REPORTER_ASSERT(r, 0.0f == tables.red()[0]);
+ REPORTER_ASSERT(r, 0.0f == tables.green()[0]);
+ REPORTER_ASSERT(r, 0.0f == tables.blue()[0]);
+ REPORTER_ASSERT(r, 1.0f == tables.red()[tables.fRed.fCount - 1]);
+ REPORTER_ASSERT(r, 1.0f == tables.green()[tables.fGreen.fCount - 1]);
+ REPORTER_ASSERT(r, 1.0f == tables.blue()[tables.fBlue.fCount - 1]);
+}
+
+class ICCTest {
+public:
+ static sk_sp<SkICC> MakeICC(sk_sp<SkColorSpace> space) {
+ return sk_sp<SkICC>(new SkICC(std::move(space)));
+ }
+ static sk_sp<SkICC> MakeICC(sk_sp<SkGammas> gammas) {
+ return MakeICC(sk_sp<SkColorSpace>(new SkColorSpace_XYZ(
+ kNonStandard_SkGammaNamed, std::move(gammas),
+ SkMatrix44(SkMatrix44::kIdentity_Constructor), nullptr)));
+ }
+};
+
+DEF_TEST(ICC_RawTransferFns, r) {
+ sk_sp<SkICC> srgb = ICCTest::MakeICC(SkColorSpace::MakeNamed(SkColorSpace::kSRGB_Named));
+ test_raw_transfer_fn(r, srgb.get());
+
+ sk_sp<SkICC> adobe =
+ ICCTest::MakeICC(SkColorSpace::MakeNamed(SkColorSpace::kAdobeRGB_Named));
+ test_raw_transfer_fn(r, adobe.get());
+
+ // Lookup-table based gamma curves
+ constexpr size_t tableSize = 10;
+ void* memory = sk_malloc_throw(sizeof(SkGammas) + sizeof(float) * tableSize);
+ sk_sp<SkGammas> gammas = sk_sp<SkGammas>(new (memory) SkGammas(3));
+ for (int i = 0; i < 3; ++i) {
+ gammas->fType[i] = SkGammas::Type::kTable_Type;
+ gammas->fData[i].fTable.fSize = tableSize;
+ gammas->fData[i].fTable.fOffset = 0;
+ }
+
+ float* table = SkTAddOffset<float>(memory, sizeof(SkGammas));
+ table[0] = 0.00f;
+ table[1] = 0.05f;
+ table[2] = 0.10f;
+ table[3] = 0.15f;
+ table[4] = 0.25f;
+ table[5] = 0.35f;
+ table[6] = 0.45f;
+ table[7] = 0.60f;
+ table[8] = 0.75f;
+ table[9] = 1.00f;
+ sk_sp<SkICC> tbl = ICCTest::MakeICC(gammas);
+ test_raw_transfer_fn(r, tbl.get());
+
+ // Parametric gamma curves
+ memory = sk_malloc_throw(sizeof(SkGammas) + sizeof(SkColorSpaceTransferFn));
+ gammas = sk_sp<SkGammas>(new (memory) SkGammas(3));
+ for (int i = 0; i < 3; ++i) {
+ gammas->fType[i] = SkGammas::Type::kParam_Type;
+ gammas->fData[i].fParamOffset = 0;
+ }
+
+ SkColorSpaceTransferFn* params = SkTAddOffset<SkColorSpaceTransferFn>
+ (memory, sizeof(SkGammas));
+
+ // Interval.
+ params->fD = 0.04045f;
+
+ // First equation:
+ params->fC = 1.0f / 12.92f;
+ params->fF = 0.0f;
+
+ // Second equation:
+ // Note that the function is continuous (it's actually sRGB).
+ params->fA = 1.0f / 1.055f;
+ params->fB = 0.055f / 1.055f;
+ params->fE = 0.0f;
+ params->fG = 2.4f;
+ sk_sp<SkICC> param = ICCTest::MakeICC(gammas);
+ test_raw_transfer_fn(r, param.get());
+
+ // Exponential gamma curves
+ gammas = sk_sp<SkGammas>(new SkGammas(3));
+ for (int i = 0; i < 3; ++i) {
+ gammas->fType[i] = SkGammas::Type::kValue_Type;
+ gammas->fData[i].fValue = 1.4f;
+ }
+ sk_sp<SkICC> exp = ICCTest::MakeICC(gammas);
+ test_raw_transfer_fn(r, exp.get());
+
+ gammas = sk_sp<SkGammas>(new SkGammas(3));
+ gammas->fType[0] = gammas->fType[1] = gammas->fType[2] = SkGammas::Type::kNamed_Type;
+ gammas->fData[0].fNamed = kSRGB_SkGammaNamed;
+ gammas->fData[1].fNamed = k2Dot2Curve_SkGammaNamed;
+ gammas->fData[2].fNamed = kLinear_SkGammaNamed;
+ sk_sp<SkICC> named = ICCTest::MakeICC(gammas);
+ test_raw_transfer_fn(r, named.get());
+
+ memory = sk_malloc_throw(sizeof(SkGammas) + sizeof(float) * tableSize +
+ sizeof(SkColorSpaceTransferFn));
+ gammas = sk_sp<SkGammas>(new (memory) SkGammas(3));
+
+ table = SkTAddOffset<float>(memory, sizeof(SkGammas));
+ table[0] = 0.00f;
+ table[1] = 0.15f;
+ table[2] = 0.20f;
+ table[3] = 0.25f;
+ table[4] = 0.35f;
+ table[5] = 0.45f;
+ table[6] = 0.55f;
+ table[7] = 0.70f;
+ table[8] = 0.85f;
+ table[9] = 1.00f;
+
+ params = SkTAddOffset<SkColorSpaceTransferFn>(memory,
+ sizeof(SkGammas) + sizeof(float) * tableSize);
+ params->fA = 1.0f / 1.055f;
+ params->fB = 0.055f / 1.055f;
+ params->fC = 1.0f / 12.92f;
+ params->fD = 0.04045f;
+ params->fE = 0.0f;
+ params->fF = 0.0f;
+ params->fG = 2.4f;
+
+ gammas->fType[0] = SkGammas::Type::kValue_Type;
+ gammas->fData[0].fValue = 1.2f;
+
+ gammas->fType[1] = SkGammas::Type::kTable_Type;
+ gammas->fData[1].fTable.fSize = tableSize;
+ gammas->fData[1].fTable.fOffset = 0;
+
+ gammas->fType[2] = SkGammas::Type::kParam_Type;
+ gammas->fData[2].fParamOffset = sizeof(float) * tableSize;
+ sk_sp<SkICC> nonstd = ICCTest::MakeICC(gammas);
+ test_raw_transfer_fn(r, nonstd.get());
+
+ // Reverse order of table and exponent
+ gammas->fType[1] = SkGammas::Type::kValue_Type;
+ gammas->fData[1].fValue = 1.2f;
+
+ gammas->fType[0] = SkGammas::Type::kTable_Type;
+ gammas->fData[0].fTable.fSize = tableSize;
+ gammas->fData[0].fTable.fOffset = 0;
+ sk_sp<SkICC> nonstd2 = ICCTest::MakeICC(gammas);
+ test_raw_transfer_fn(r, nonstd2.get());
+}