From: Steinar H. Gunderson <sgunderson@bigfoot.com>
Date: Sat, 27 Feb 2016 23:28:31 +0000 (+0100)
Subject: Add some sRGB conversion functions to test_util.{h,cpp}.
X-Git-Tag: 1.4.0~13
X-Git-Url: https://git.sesse.net/?p=movit;a=commitdiff_plain;h=d2eee22b0440147f69038e3cf829910b18526efc

Add some sRGB conversion functions to test_util.{h,cpp}.
---

diff --git a/gamma_compression_effect_test.cpp b/gamma_compression_effect_test.cpp
index 1c87680..db20234 100644
--- a/gamma_compression_effect_test.cpp
+++ b/gamma_compression_effect_test.cpp
@@ -54,13 +54,7 @@ TEST(GammaCompressionEffectTest, sRGB_Accuracy) {
 		double x = i / 255.0;
 
 		expected_data[i] = x;
-
-		// From the Wikipedia article on sRGB.
-		if (x < 0.04045) {
-			data[i] = x / 12.92;
-		} else {
-			data[i] = pow((x + 0.055) / 1.055, 2.4);
-		}
+		data[i] = srgb_to_linear(x);
 	}
 
 	EffectChainTester tester(data, 256, 1, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_LINEAR, GL_RGBA32F);
diff --git a/gamma_expansion_effect_test.cpp b/gamma_expansion_effect_test.cpp
index 499a0d4..1e399dc 100644
--- a/gamma_expansion_effect_test.cpp
+++ b/gamma_expansion_effect_test.cpp
@@ -62,13 +62,7 @@ TEST(GammaExpansionEffectTest, sRGB_Accuracy) {
 		double x = i / 255.0;
 
 		data[i] = x;
-
-		// From the Wikipedia article on sRGB.
-		if (x < 0.04045) {
-			expected_data[i] = x / 12.92;
-		} else {
-			expected_data[i] = pow((x + 0.055) / 1.055, 2.4);
-		}
+		expected_data[i] = srgb_to_linear(x);
 	}
 
 	EffectChainTester tester(data, 256, 1, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_sRGB, GL_RGBA32F);
diff --git a/test_util.cpp b/test_util.cpp
index b377309..05eac31 100644
--- a/test_util.cpp
+++ b/test_util.cpp
@@ -351,4 +351,24 @@ void test_accuracy(const float *expected, const float *result, unsigned num_valu
 	EXPECT_LT(rms, rms_limit);
 }
 
+double srgb_to_linear(double x)
+{
+	// From the Wikipedia article on sRGB.
+	if (x < 0.04045) {
+		return x / 12.92;
+	} else {
+		return pow((x + 0.055) / 1.055, 2.4);
+	}
+}
+
+double linear_to_srgb(double x)
+{
+	// From the Wikipedia article on sRGB.
+	if (x < 0.0031308) {
+		return 12.92 * x;
+	} else {
+		return 1.055 * pow(x, 1.0 / 2.4) - 0.055;
+	}
+}
+
 }  // namespace movit
diff --git a/test_util.h b/test_util.h
index 69efe35..43d0216 100644
--- a/test_util.h
+++ b/test_util.h
@@ -48,6 +48,14 @@ void expect_equal(const float *ref, const float *result, unsigned width, unsigne
 void expect_equal(const unsigned char *ref, const unsigned char *result, unsigned width, unsigned height, unsigned largest_difference_limit = 1, float rms_limit = 0.2);
 void test_accuracy(const float *expected, const float *result, unsigned num_values, double absolute_error_limit, double relative_error_limit, double local_relative_error_limit, double rms_limit);
 
+// Convert an sRGB encoded value (0.0 to 1.0, inclusive) to linear light.
+// Undefined for values outside 0.0..1.0.
+double srgb_to_linear(double x);
+
+// Convert a value in linear light (0.0 to 1.0, inclusive) to sRGB.
+// Undefined for values outside 0.0..1.0.
+double linear_to_srgb(double x);
+
 }  // namespace movit
 
 #endif  // !defined(_MOVIT_TEST_UTIL_H)