Add support for floats

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 80 insertions, 76 deletions

diff --git a/src/blind-set-luma.c b/src/blind-set-luma.c
index 751bc6b..2c2b885 100644
--- a/src/blind-set-luma.c
+++ b/src/blind-set-luma.c
@@ -9,82 +9,84 @@
 
 USAGE("luma-stream")
 
-static void
-process_xyza(struct stream *colour, struct stream *luma, size_t n)
-{
-	size_t i;
-	double a, y;
-	for (i = 0; i < n; i += colour->pixel_size) {
-		a = ((double *)(luma->buf + i))[1];
-		a *= ((double *)(luma->buf + i))[3];
-		y = ((double *)(colour->buf + i))[1];
-		((double *)(colour->buf + i))[0] += y * a - y;
-		((double *)(colour->buf + i))[1]  = y * a;
-		((double *)(colour->buf + i))[2] += y * a - y;
-		/*
-		 * Note, this changes the luma only, not the saturation,
-		 * so the result may look a bit weird. To change both
-		 * you can use `blind-arithm mul`.
-		 * 
-		 * Explaination of algorithm:
-		 * 
-		 *   Y is the luma, but (X, Z) is not the chroma,
-		 *   but in CIELAB, L* is the luma and (a*, *b) is
-		 *   the chroma. Multiplying
-		 *   
-		 *      ⎛0 1   0⎞
-		 *      ⎜1 −1  0⎟
-		 *      ⎝0  1 −1⎠
-		 *   
-		 *   (X Y Z)' gives a colour model similar to
-		 *   CIE L*a*b*: a model where each parameter is
-		 *   a linear transformation of the corresponding
-		 *   parameter in CIE L*a*b*. The inverse of that
-		 *   matrix is
-		 *   
-		 *      ⎛1 1  0⎞
-		 *      ⎜1 0  0⎟
-		 *      ⎝0 0 −1⎠
-		 *   
-		 *   and
-		 *   
-		 *      ⎛1 1  0⎞⎛a 0 0⎞⎛0 1   0⎞   ⎛1 a−1 0⎞
-		 *      ⎜1 0  0⎟⎜0 1 0⎟⎜1 −1  0⎟ = ⎜0  a  0⎟.
-		 *      ⎝0 0 −1⎠⎝0 0 1⎠⎝0  1 −1⎠   ⎝0 a−1 1⎠
-		 * 
-		 * Explanation of why changing only the luma looks weird:
-		 * 
-		 *   Consider when you are workings with colours,
-		 *   when you want to change the brightness of a
-		 *   colour, you multiply all parameters: red, green,
-		 *   and blue, with the same value (this is however
-		 *   only an approximation in most cases, since you
-		 *   are usually usally working with colours that
-		 *   have the sRGB transfer function applied to their
-		 *   parameters). This action is the same in all
-		 *   colour models and colour spaces that are a
-		 *   linear transformation of the sRGB colour spaces
-		 *   (sans transfer function); this is simply because
-		 *   of the properties of linear transformations.
-		 * 
-		 *   The reason you change brightness this way can
-		 *   be explained by how objects reflect colour.
-		 *   Objects can only reject colours that are present
-		 *   in the light source. A ideal white object will look
-		 *   pure red if the light sources is ideal red, and a
-		 *   a ideal blue object will pure black in the same
-		 *   light source. An object can also not reflect
-		 *   colours brighter than the source. When the brightness
-		 *   of a light source is changed, the intensity of all
-		 *   colours (by wavelength) it emits is multiplied by
-		 *   one value. Therefore, when changing the brightness
-		 *   it looks most natural when all primaries (red, green,
-		 *   and blue) are multiplied by one value, or all
-		 *   parameters of the used colour spaces is a linear
-		 *   transformation of sRGB, such as CIE XYZ.
-		 */
-	}
-}
+#define PROCESS(TYPE)\
+	do {\
+		size_t i;\
+		TYPE a, y;\
+		for (i = 0; i < n; i += colour->pixel_size) {\
+			a = ((TYPE *)(luma->buf + i))[1];\
+			a *= ((TYPE *)(luma->buf + i))[3];\
+			y = ((TYPE *)(colour->buf + i))[1];\
+			((TYPE *)(colour->buf + i))[0] += y * a - y;\
+			((TYPE *)(colour->buf + i))[1]  = y * a;\
+			((TYPE *)(colour->buf + i))[2] += y * a - y;\
+			/*
+			 * Note, this changes the luma only, not the saturation,
+			 * so the result may look a bit weird. To change both
+			 * you can use `blind-arithm mul`.
+			 * 
+			 * Explaination of algorithm:
+			 * 
+			 *   Y is the luma, but (X, Z) is not the chroma,
+			 *   but in CIELAB, L* is the luma and (a*, *b) is
+			 *   the chroma. Multiplying
+			 *   
+			 *      ⎛0 1   0⎞
+			 *      ⎜1 −1  0⎟
+			 *      ⎝0  1 −1⎠
+			 *   
+			 *   (X Y Z)' gives a colour model similar to
+			 *   CIE L*a*b*: a model where each parameter is
+			 *   a linear transformation of the corresponding
+			 *   parameter in CIE L*a*b*. The inverse of that
+			 *   matrix is
+			 *   
+			 *      ⎛1 1  0⎞
+			 *      ⎜1 0  0⎟
+			 *      ⎝0 0 −1⎠
+			 *   
+			 *   and
+			 *   
+			 *      ⎛1 1  0⎞⎛a 0 0⎞⎛0 1   0⎞   ⎛1 a−1 0⎞
+			 *      ⎜1 0  0⎟⎜0 1 0⎟⎜1 −1  0⎟ = ⎜0  a  0⎟.
+			 *      ⎝0 0 −1⎠⎝0 0 1⎠⎝0  1 −1⎠   ⎝0 a−1 1⎠
+			 * 
+			 * Explanation of why changing only the luma looks weird:
+			 * 
+			 *   Consider when you are workings with colours,
+			 *   when you want to change the brightness of a
+			 *   colour, you multiply all parameters: red, green,
+			 *   and blue, with the same value (this is however
+			 *   only an approximation in most cases, since you
+			 *   are usually usally working with colours that
+			 *   have the sRGB transfer function applied to their
+			 *   parameters). This action is the same in all
+			 *   colour models and colour spaces that are a
+			 *   linear transformation of the sRGB colour spaces
+			 *   (sans transfer function); this is simply because
+			 *   of the properties of linear transformations.
+			 * 
+			 *   The reason you change brightness this way can
+			 *   be explained by how objects reflect colour.
+			 *   Objects can only reject colours that are present
+			 *   in the light source. A ideal white object will look
+			 *   pure red if the light sources is ideal red, and a
+			 *   a ideal blue object will pure black in the same
+			 *   light source. An object can also not reflect
+			 *   colours brighter than the source. When the brightness
+			 *   of a light source is changed, the intensity of all
+			 *   colours (by wavelength) it emits is multiplied by
+			 *   one value. Therefore, when changing the brightness
+			 *   it looks most natural when all primaries (red, green,
+			 *   and blue) are multiplied by one value, or all
+			 *   parameters of the used colour spaces is a linear
+			 *   transformation of sRGB, such as CIE XYZ.
+			 */\
+		}\
+	} while (0)
+
+static void process_xyza (struct stream *colour, struct stream *luma, size_t n) {PROCESS(double);}
+static void process_xyzaf(struct stream *colour, struct stream *luma, size_t n) {PROCESS(float);}
 
 int
 main(int argc, char *argv[])
@@ -99,6 +101,8 @@ main(int argc, char *argv[])
 
 	if (!strcmp(colour.pixfmt, "xyza"))
 		process = process_xyza;
+	else if (!strcmp(colour.pixfmt, "xyza f"))
+		process = process_xyzaf;
 	else
 		eprintf("pixel format %s is not supported, try xyza\n", colour.pixfmt);