pixman-filter: Consistency in arg names to integral ()

Rename kernel1/2 to reconstruct/sample to match the other functions.
Rename "scale" to "size" to avoid confusion with the scale being applied
to the image, which is the reciprocol of this value.

v10: Renamed "scale" to "size"

Signed-off-by: Bill Spitzak <spitzak@gmail.com>
Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>

2 files changed, 26 insertions, 28 deletions

diff --git a/pixman/pixman-filter.c b/pixman/pixman-filter.c
index 3981c8b..b70da1f 100644
--- a/pixman/pixman-filter.c
+++ b/pixman/pixman-filter.c
@@ -147,8 +147,8 @@ static const filter_info_t filters[] =
     { PIXMAN_KERNEL_LANCZOS3_STRETCHED, nice_kernel,      8.0 },
 };
 
-/* This function scales @kernel2 by @scale, then
- * aligns @x1 in @kernel1 with @x2 in @kernel2 and
+/* This function scales the @sample filter by @size, then
+ * aligns @x1 in @reconstruct with @x2 in @sample and
  * and integrates the product of the kernels across @width.
  *
  * This function assumes that the intervals are within
@@ -156,8 +156,8 @@ static const filter_info_t filters[] =
  * try to integrate a linear kernel ouside of [-1:1]
  */
 static double
-integral (pixman_kernel_t kernel1, double x1,
-	  pixman_kernel_t kernel2, double scale, double x2,
+integral (pixman_kernel_t reconstruct, double x1,
+	  pixman_kernel_t sample, double size, double x2,
 	  double width)
 {
     /* If the integration interval crosses zero, break it into
@@ -168,31 +168,31 @@ integral (pixman_kernel_t kernel1, double x1,
     if (x1 < 0 && x1 + width > 0)
     {
 	return
-	    integral (kernel1, x1, kernel2, scale, x2, - x1) +
-	    integral (kernel1, 0, kernel2, scale, x2 - x1, width + x1);
+	    integral (reconstruct, x1, sample, size, x2, - x1) +
+	    integral (reconstruct, 0, sample, size, x2 - x1, width + x1);
     }
     else if (x2 < 0 && x2 + width > 0)
     {
 	return
-	    integral (kernel1, x1, kernel2, scale, x2, - x2) +
-	    integral (kernel1, x1 - x2, kernel2, scale, 0, width + x2);
+	    integral (reconstruct, x1, sample, size, x2, - x2) +
+	    integral (reconstruct, x1 - x2, sample, size, 0, width + x2);
     }
-    else if (kernel1 == PIXMAN_KERNEL_IMPULSE)
+    else if (reconstruct == PIXMAN_KERNEL_IMPULSE)
     {
 	assert (width == 0.0);
-	return filters[kernel2].func (x2 * scale);
+	return filters[sample].func (x2 / size);
     }
-    else if (kernel2 == PIXMAN_KERNEL_IMPULSE)
+    else if (sample == PIXMAN_KERNEL_IMPULSE)
     {
 	assert (width == 0.0);
-	return filters[kernel1].func (x1);
+	return filters[reconstruct].func (x1);
     }
     else
     {
 	/* Integration via Simpson's rule */
 #define N_SEGMENTS 128
 #define SAMPLE(a1, a2)							\
-	(filters[kernel1].func ((a1)) * filters[kernel2].func ((a2) * scale))
+	(filters[reconstruct].func ((a1)) * filters[sample].func ((a2) / size))
 	
 	double s = 0.0;
 	double h = width / (double)N_SEGMENTS;
@@ -221,16 +221,14 @@ static pixman_fixed_t *
 create_1d_filter (int             *width,
 		  pixman_kernel_t  reconstruct,
 		  pixman_kernel_t  sample,
-		  double           scale,
+		  double           size,
 		  int              n_phases)
 {
     pixman_fixed_t *params, *p;
     double step;
-    double size;
     int i;
 
-    size = scale * filters[sample].width + filters[reconstruct].width;
-    *width = ceil (size);
+    *width = ceil (size * filters[sample].width + filters[reconstruct].width);
 
     p = params = malloc (*width * n_phases * sizeof (pixman_fixed_t));
     if (!params)
@@ -259,8 +257,8 @@ create_1d_filter (int             *width,
 	    double pos = x + 0.5 - frac;
 	    double rlow = - filters[reconstruct].width / 2.0;
 	    double rhigh = rlow + filters[reconstruct].width;
-	    double slow = pos - scale * filters[sample].width / 2.0;
-	    double shigh = slow + scale * filters[sample].width;
+	    double slow = pos - size * filters[sample].width / 2.0;
+	    double shigh = slow + size * filters[sample].width;
 	    double c = 0.0;
 	    double ilow, ihigh;
 
@@ -270,7 +268,7 @@ create_1d_filter (int             *width,
 		ihigh = MIN (shigh, rhigh);
 
 		c = integral (reconstruct, ilow,
-			      sample, 1.0 / scale, ilow - pos,
+			      sample, size, ilow - pos,
 			      ihigh - ilow);
 	    }
 
@@ -339,12 +337,12 @@ gnuplot_filter(int width, int samples, const pixman_fixed_t* p)
 #endif
 
 /* Create the parameter list for a SEPARABLE_CONVOLUTION filter
- * with the given kernels and scale parameters
+ * with the given kernels and size parameters
  */
 PIXMAN_EXPORT pixman_fixed_t *
 pixman_filter_create_separable_convolution (int             *n_values,
-					    pixman_fixed_t   scale_x,
-					    pixman_fixed_t   scale_y,
+					    pixman_fixed_t   size_x,
+					    pixman_fixed_t   size_y,
 					    pixman_kernel_t  reconstruct_x,
 					    pixman_kernel_t  reconstruct_y,
 					    pixman_kernel_t  sample_x,
@@ -352,8 +350,8 @@ pixman_filter_create_separable_convolution (int             *n_values,
 					    int              subsample_bits_x,
 					    int	             subsample_bits_y)
 {
-    double sx = fabs (pixman_fixed_to_double (scale_x));
-    double sy = fabs (pixman_fixed_to_double (scale_y));
+    double sx = fabs (pixman_fixed_to_double (size_x));
+    double sy = fabs (pixman_fixed_to_double (size_y));
     pixman_fixed_t *horz = NULL, *vert = NULL, *params = NULL;
     int subsample_x, subsample_y;
     int width, height;
diff --git a/pixman/pixman.h b/pixman/pixman.h
index 509ba5e..b012a33 100644
--- a/pixman/pixman.h
+++ b/pixman/pixman.h
@@ -845,12 +845,12 @@ typedef enum
 } pixman_kernel_t;
 
 /* Create the parameter list for a SEPARABLE_CONVOLUTION filter
- * with the given kernels and scale parameters.
+ * with the given kernels and size parameters.
  */
 pixman_fixed_t *
 pixman_filter_create_separable_convolution (int             *n_values,
-					    pixman_fixed_t   scale_x,
-					    pixman_fixed_t   scale_y,
+					    pixman_fixed_t   size_x,
+					    pixman_fixed_t   size_y,
 					    pixman_kernel_t  reconstruct_x,
 					    pixman_kernel_t  reconstruct_y,
 					    pixman_kernel_t  sample_x,