misc refined

src/render.rs

@@ -228,16 +228,17 @@ impl PathBuilderExt for skia::PathBuilder {
     }
 }
 
+// https://github.com/TinyVG/sdk/blob/ed01b9112/src/lib/rendering.zig#L1133
 /* fn lerp_sRGB(c0: RGBA8888, c1: RGBA8888, f_unchecked: f32) -> RGBA8888 { // blend
     //  Color interpolation is needed in gradients and must performed in linear
     //  color space. This means that the value from the color table needs to be
     //  converted to linear color space, then each color component is
     //  interpolated linearly and the final color is then determined by
     //  converting the color back to the specified color space.
     let f = f32::clamp(f_unchecked, 0.0, 1.0);  RGBA8888 {
-        r: gamma2linear(lerp(linear2gamma(c0.r), linear2gamma(c1.r), f)),
-        g: gamma2linear(lerp(linear2gamma(c0.g), linear2gamma(c1.g), f)),
-        b: gamma2linear(lerp(linear2gamma(c0.b), linear2gamma(c1.b), f)),
+        r: linear2gamma(lerp(gamma2linear(c0.r), gamma2linear(c1.r), f)),
+        g: linear2gamma(lerp(gamma2linear(c0.g), gamma2linear(c1.g), f)),
+        b: linear2gamma(lerp(gamma2linear(c0.b), gamma2linear(c1.b), f)),
         a: (lerp(c0.a as f32 / 255.0, c1.a as f32 / 255.0, f) * 255.0) as _,
     }
 }
@@ -250,7 +251,7 @@ fn lerp_value(src: f32, dst: f32, src_alpha: f32, dst_alpha: f32, fin_alpha: f32
 const sRGB_gamma: f32 = 2.2;
 #[inline] fn  mapToLinear(v: f32) -> f32 { f32::powf(v, sRGB_gamma) }
 #[inline] fn  mapToGamma (v: f32) -> f32 { f32::powf(v, 1.0 / sRGB_gamma) }
-#[inline] fn gamma2linear(v: f32) ->  u8 { (255.0 * mapToGamma(v)) as _ }
-#[inline] fn linear2gamma(v:  u8) -> f32 { mapToLinear(v as f32 / 255.0) }
+#[inline] fn linear2gamma(v: f32) ->  u8 { (255.0 * mapToGamma(v)) as _ }
+#[inline] fn gamma2linear(v:  u8) -> f32 { mapToLinear(v as f32 / 255.0) }
 #[inline] fn lerp(a: f32, b: f32, f: f32) -> f32 { a + (b - a) * f } */
 

src/tinyvg.rs

@@ -48,23 +48,21 @@ impl From<TryFromIntError> for TVGError {
 /// and a sequence of commands terminated by a _end of file_ command.
 ///
 /// - All integers are assumed to be encoded in little-endian byte order
-/// if not specified otherwise.
+///   if not specified otherwise.
 ///
-/// - The _Type_ fields have no padding bits in between. If a field
-/// does not align to a byte boundary, the next field will be offset
-/// into the byte by the current fields bit offset + bit size.
-/// This means, that two consecutive fields A (u3) and B (u5) can be
-/// extracted from the byte by using (byte & 0x7) >> 0 for A and
-/// (byte & 0xF8) >> 3 for B.
+/// - The _Type_ fields have no padding bits in between. If a field does not align to
+///   a byte boundary, the next field will be offset into the byte by the current
+///   fields bit offset + bit size. This means, that two consecutive fields A (u3) and
+///   B (u5) can be extracted from the byte by using (byte & 0x7) >> 0 for A and
+///   (byte & 0xF8) >> 3 for B.
 ///
 /// - If not specified otherwise, all coordinates in TinyVG are absolute
-/// coordinates, including path nodes and gradients.
+///   coordinates, including path nodes and gradients.
 ///
-/// - A lot of encoded integers are encoded off-by-one, thus mapping 0 to
-/// 1, 1 to 2 and so on. This is done as encoding these integers as 0
-/// would be equivalent to removing the element from the file.
-/// Thus, this can be used to encode some more elements with less bytes.
-/// If this is the case, this is signaled by the use of value+1.
+/// - A lot of encoded integers are encoded off-by-one, thus mapping 0 to 1, 1 to 2 and so on.
+///   This is done as encoding these integers as 0 would be equivalent to removing the element
+///   from the file. Thus, this can be used to encode some more elements with less bytes.
+///   If this is the case, this is signaled by the use of value+1.
 ///
 /// https://tinyvg.tech/download/specification.txt, https://github.com/TinyVG/sdk,
 /// https://github.com/lily-mara/tinyvg-rs, https://github.com/dataphract/tinyvg-rs