Vendor dependencies for 0.3.0 release

vendor/png/src/srgb.rs

@@ -0,0 +1,30 @@
+use crate::{ScaledFloat, SourceChromaticities};
+
+/// Get the gamma that should be substituted for images conforming to the sRGB color space.
+pub fn substitute_gamma() -> ScaledFloat {
+    // Value taken from https://www.w3.org/TR/2003/REC-PNG-20031110/#11sRGB
+    ScaledFloat::from_scaled(45455)
+}
+
+/// Get the chromaticities that should be substituted for images conforming to the sRGB color space.
+pub fn substitute_chromaticities() -> SourceChromaticities {
+    // Values taken from https://www.w3.org/TR/2003/REC-PNG-20031110/#11sRGB
+    SourceChromaticities {
+        white: (
+            ScaledFloat::from_scaled(31270),
+            ScaledFloat::from_scaled(32900),
+        ),
+        red: (
+            ScaledFloat::from_scaled(64000),
+            ScaledFloat::from_scaled(33000),
+        ),
+        green: (
+            ScaledFloat::from_scaled(30000),
+            ScaledFloat::from_scaled(60000),
+        ),
+        blue: (
+            ScaledFloat::from_scaled(15000),
+            ScaledFloat::from_scaled(6000),
+        ),
+    }
+}