[gthumb] cairo scale: removed EPSILON

[Paolo Bacchilega <paobac src gnome org>]

commit 07799845bfee8995c4bb0f0fea6e9ba379f9ee30
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Sun Nov 29 16:45:38 2020 +0100

    cairo scale: removed EPSILON

 gthumb/cairo-scale.c | 32 +++++++++-----------------------
 1 file changed, 9 insertions(+), 23 deletions(-)
---
diff --git a/gthumb/cairo-scale.c b/gthumb/cairo-scale.c
index e52ae856..4c4a37ab 100644
--- a/gthumb/cairo-scale.c
+++ b/gthumb/cairo-scale.c
@@ -29,9 +29,6 @@
 #include "glib-utils.h"
 
 
-#define EPSILON ((ScaleReal) 1.0e-16)
-
-
 typedef double ScaleReal;
 typedef ScaleReal (*weight_func_t) (ScaleReal distance);
 
@@ -352,21 +349,12 @@ resize_filter_destroy (resize_filter_t *resize_filter)
 }
 
 
-static inline ScaleReal
-reciprocal (ScaleReal x)
-{
-       ScaleReal sign = x < 0.0 ? -1.0 : 1.0;
-       return (sign * x) >= EPSILON ? 1.0 / x : sign * (1.0 / EPSILON);
-}
-
-
 static void
 horizontal_scale_transpose (cairo_surface_t *image,
                            cairo_surface_t *scaled,
                            ScaleReal        scale_factor,
                            resize_filter_t *resize_filter)
 {
-       ScaleReal  scale;
        ScaleReal  support;
        int        y;
        int        image_width;
@@ -381,12 +369,9 @@ horizontal_scale_transpose (cairo_surface_t *image,
        if (resize_filter->cancelled)
                return;
 
-       scale = MAX ((ScaleReal) 1.0 / scale_factor + EPSILON, 1.0);
-       support = scale * resize_filter_get_support (resize_filter);
-       if (support < 0.5) {
+       support = (1.0 / scale_factor) * resize_filter_get_support (resize_filter);
+       if (support < 0.5)
                support = 0.5;
-               scale = 1.0;
-       }
 
        image_width = cairo_image_surface_get_width (image);
        scaled_width = cairo_image_surface_get_width (scaled);
@@ -397,7 +382,6 @@ horizontal_scale_transpose (cairo_surface_t *image,
        dest_rowstride = cairo_image_surface_get_stride (scaled);
        weights = g_new (ScaleReal, 2.0 * support + 3.0);
 
-       scale = reciprocal (scale);
        for (y = 0; y < scaled_height; y++) {
                guchar    *p_src_row;
                guchar    *p_dest_pixel;
@@ -424,13 +408,15 @@ horizontal_scale_transpose (cairo_surface_t *image,
                        gth_async_task_set_data (resize_filter->task, NULL, NULL, &progress);
                }
 
-               bisect = ((ScaleReal) y + 0.5) / scale_factor + EPSILON;
-               start = MAX (bisect - support + 0.5, 0);
-               stop = MIN (bisect + support + 0.5, (ScaleReal) image_width);
+               bisect = ((ScaleReal) y + 0.5) / scale_factor;
+               start = bisect - support + 0.5;
+               start = MAX (start, 0);
+               stop = bisect + support + 0.5;
+               stop = MIN (stop, image_width);
 
                density = 0.0;
                for (n = 0; n < stop - start; n++) {
-                       weights[n] = resize_filter_get_weight (resize_filter, scale * ((ScaleReal) (start + 
n) - bisect + 0.5));
+                       weights[n] = resize_filter_get_weight (resize_filter, scale_factor * ((ScaleReal) 
(start + n) - bisect + 0.5));
                        density += weights[n];
                }
 
@@ -440,7 +426,7 @@ horizontal_scale_transpose (cairo_surface_t *image,
                */
 
                if ((density != 0.0) && (density != 1.0)) {
-                       density = reciprocal (density);
+                       density = 1.0 / density;
                        for (i = 0; i < n; i++)
                                weights[i] *= density;
                }