diff options
author | Matt Sarett <msarett@google.com> | 2016-10-11 16:57:50 -0400 |
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committer | Skia Commit-Bot <skia-commit-bot@chromium.org> | 2016-10-11 21:59:09 +0000 |
commit | df44fc5f2bb282557df291e20dbd26c070533aa6 (patch) | |
tree | 294b40001d8928e59771848e12efb70956922b58 /src/core/SkColorSpacePriv.h | |
parent | 3eb71216d2fb70114417ae8ee9b0c5f5dc650704 (diff) |
Add SkColorSpaceTransferFn to SkColorSpace
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=3178
Change-Id: I354342d4469cee0e25a7b0d189e925e431da623c
Reviewed-on: https://skia-review.googlesource.com/3178
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Matt Sarett <msarett@google.com>
Diffstat (limited to 'src/core/SkColorSpacePriv.h')
-rw-r--r-- | src/core/SkColorSpacePriv.h | 76 |
1 files changed, 75 insertions, 1 deletions
diff --git a/src/core/SkColorSpacePriv.h b/src/core/SkColorSpacePriv.h index e7c8aaa103..73038738ff 100644 --- a/src/core/SkColorSpacePriv.h +++ b/src/core/SkColorSpacePriv.h @@ -7,6 +7,80 @@ #define SkColorSpacePrintf(...) -inline bool color_space_almost_equal(float a, float b) { +static inline bool color_space_almost_equal(float a, float b) { return SkTAbs(a - b) < 0.01f; } + +static inline bool is_zero_to_one(float v) { + return (0.0f <= v) && (v <= 1.0f); +} + +static inline bool is_valid_transfer_fn(const SkColorSpaceTransferFn& coeffs) { + if (SkScalarIsNaN(coeffs.fA) || SkScalarIsNaN(coeffs.fB) || + SkScalarIsNaN(coeffs.fC) || SkScalarIsNaN(coeffs.fD) || + SkScalarIsNaN(coeffs.fE) || SkScalarIsNaN(coeffs.fF) || + SkScalarIsNaN(coeffs.fG)) + { + return false; + } + + if (!is_zero_to_one(coeffs.fD)) { + return false; + } + + if (coeffs.fD == 0.0f) { + // Y = (aX + b)^g + c for always + if (0.0f == coeffs.fA || 0.0f == coeffs.fG) { + SkColorSpacePrintf("A or G is zero, constant transfer function " + "is nonsense"); + return false; + } + } + + if (coeffs.fD == 1.0f) { + // Y = eX + f for always + if (0.0f == coeffs.fE) { + SkColorSpacePrintf("E is zero, constant transfer function is " + "nonsense"); + return false; + } + } + + if ((0.0f == coeffs.fA || 0.0f == coeffs.fG) && 0.0f == coeffs.fE) { + SkColorSpacePrintf("A or G, and E are zero, constant transfer function " + "is nonsense"); + return false; + } + + if (coeffs.fE < 0.0f) { + SkColorSpacePrintf("Transfer function must be increasing"); + return false; + } + + if (coeffs.fA < 0.0f || coeffs.fG < 0.0f) { + SkColorSpacePrintf("Transfer function must be positive or increasing"); + return false; + } + + return true; +} + +static inline bool is_almost_srgb(const SkColorSpaceTransferFn& coeffs) { + return color_space_almost_equal(0.9479f, coeffs.fA) && + color_space_almost_equal(0.0521f, coeffs.fB) && + color_space_almost_equal(0.0000f, coeffs.fC) && + color_space_almost_equal(0.0405f, coeffs.fD) && + color_space_almost_equal(0.0774f, coeffs.fE) && + color_space_almost_equal(0.0000f, coeffs.fF) && + color_space_almost_equal(2.4000f, coeffs.fG); +} + +static inline bool is_almost_2dot2(const SkColorSpaceTransferFn& coeffs) { + return color_space_almost_equal(1.0f, coeffs.fA) && + color_space_almost_equal(0.0f, coeffs.fB) && + color_space_almost_equal(0.0f, coeffs.fC) && + color_space_almost_equal(0.0f, coeffs.fD) && + color_space_almost_equal(0.0f, coeffs.fE) && + color_space_almost_equal(0.0f, coeffs.fF) && + color_space_almost_equal(2.2f, coeffs.fG); +} |