fixed problems with floor/ceil

- introduce macros ROUND_DOWN, ROUND_UP
- fixed incorrect usage of floor/ceil functions on int arguments

patch by  Yuriy Kaminskiy

diff --git a/src/pixbuf-renderer.c b/src/pixbuf-renderer.c
index f9d31f1..8bea065 100644 (file)
--- a/src/pixbuf-renderer.c
+++ b/src/pixbuf-renderer.c
@@ -79,6 +79,10 @@ typedef enum {
  */
 #define PR_MIN_SCALE_SIZE 8
 
+/* round A up/down to integer count of B */
+#define ROUND_UP(A,B)   ((gint)(((A)+(B)-1)/(B))*(B))
+#define ROUND_DOWN(A,B) ((gint)(((A))/(B))*(B))
+
 typedef enum {
        TILE_RENDER_NONE = 0,   /* do nothing */
        TILE_RENDER_AREA,       /* render an area of the tile */
@@ -1468,10 +1472,10 @@ static gboolean pr_source_tile_visible(PixbufRenderer *pr, SourceTile *st)
 
        if (!st) return FALSE;
 
-       x1 = (pr->x_scroll / pr->tile_width) * pr->tile_width;
-       y1 = (pr->y_scroll / pr->tile_height) * pr->tile_height;
-       x2 = ((pr->x_scroll + pr->vis_width) / pr->tile_width) * pr->tile_width + pr->tile_width;
-       y2 = ((pr->y_scroll + pr->vis_height) / pr->tile_height) * pr->tile_height + pr->tile_height;
+       x1 = ROUND_DOWN(pr->x_scroll, pr->tile_width);
+       y1 = ROUND_DOWN(pr->y_scroll, pr->tile_height);
+       x2 = ROUND_UP(pr->x_scroll + pr->vis_width, pr->tile_width);
+       y2 = ROUND_UP(pr->y_scroll + pr->vis_height, pr->tile_height);
 
        return !((gdouble)st->x * pr->scale > (gdouble)x2 ||
                 (gdouble)(st->x + pr->source_tile_width) * pr->scale < (gdouble)x1 ||
@@ -1533,8 +1537,8 @@ static SourceTile *pr_source_tile_new(PixbufRenderer *pr, gint x, gint y)
                                            pr->source_tile_width, pr->source_tile_height);
                }
 
-       st->x = (x / pr->source_tile_width) * pr->source_tile_width;
-       st->y = (y / pr->source_tile_height) * pr->source_tile_height;
+       st->x = ROUND_DOWN(x, pr->source_tile_width);
+       st->y = ROUND_DOWN(y, pr->source_tile_height);
        st->blank = TRUE;
 
        pr->source_tiles = g_list_prepend(pr->source_tiles, st);
@@ -1599,8 +1603,8 @@ static GList *pr_source_tile_compute_region(PixbufRenderer *pr, gint x, gint y,
        if (w > pr->image_width) w = pr->image_width;
        if (h > pr->image_height) h = pr->image_height;
 
-       sx = (x / pr->source_tile_width) * pr->source_tile_width;
-       sy = (y / pr->source_tile_height) * pr->source_tile_height;
+       sx = ROUND_DOWN(x, pr->source_tile_width);
+       sy = ROUND_DOWN(y, pr->source_tile_height);
 
        for (x1 = sx; x1 < x + w; x1+= pr->source_tile_width)
                {
@@ -2019,11 +2023,11 @@ static void pr_tile_invalidate_region(PixbufRenderer *pr, gint x, gint y, gint w
        gint y1, y2;
        GList *work;
 
-       x1 = (gint)floor(x / pr->tile_width) * pr->tile_width;
-       x2 = (gint)ceil((x + w) / pr->tile_width) * pr->tile_width;
+       x1 = ROUND_DOWN(x, pr->tile_width);
+       x2 = ROUND_UP(x + w, pr->tile_width);
 
-       y1 = (gint)floor(y / pr->tile_height) * pr->tile_height;
-       y2 = (gint)ceil((y + h) / pr->tile_height) * pr->tile_height;
+       y1 = ROUND_DOWN(y, pr->tile_height);
+       y2 = ROUND_UP(y + h, pr->tile_height);
 
        work = pr->tiles;
        while (work)
@@ -3015,11 +3019,11 @@ static gboolean pr_queue_to_tiles(PixbufRenderer *pr, gint x, gint y, gint w, gi
 
        if (clamp && !pr_clamp_to_visible(pr, &x, &y, &w, &h)) return FALSE;
 
-       x1 = (gint)floor(x / pr->tile_width) * pr->tile_width;
-       x2 = (gint)ceil((x + w) / pr->tile_width) * pr->tile_width;
+       x1 = ROUND_DOWN(x, pr->tile_width);
+       x2 = ROUND_UP(x + w, pr->tile_width);
 
-       y1 = (gint)floor(y / pr->tile_height) * pr->tile_height;
-       y2 = (gint)ceil((y + h) / pr->tile_height) * pr->tile_height;
+       y1 = ROUND_DOWN(y, pr->tile_height);
+       y2 = ROUND_UP(y + h, pr->tile_height);
 
        for (j = y1; j <= y2; j += pr->tile_height)
                {