UV: extend custom grid sizes to set each axis separately

For example, allows a custom UV grid size of 4 x 12.

TODO: Fix snapping with custom UV grid sizes.

Manifest Tasks: T78391

Differential Revision: https://developer.blender.org/D16000

2 files changed, 12 insertions, 10 deletions

diff --git a/source/blender/editors/space_image/image_draw.c b/source/blender/editors/space_image/image_draw.c
index 37a6e6dfcb1..8a934396229 100644
--- a/source/blender/editors/space_image/image_draw.c
+++ b/source/blender/editors/space_image/image_draw.c
@@ -585,18 +585,19 @@ float ED_space_image_zoom_level(const View2D *v2d, const int grid_dimension)
 }
 
 void ED_space_image_grid_steps(SpaceImage *sima,
-                               float grid_steps[SI_GRID_STEPS_LEN],
+                               float grid_steps_x[SI_GRID_STEPS_LEN],
+                               float grid_steps_y[SI_GRID_STEPS_LEN],
                                const int grid_dimension)
 {
-  if (sima->flag & SI_CUSTOM_GRID) {
-    for (int step = 0; step < SI_GRID_STEPS_LEN; step++) {
-      grid_steps[step] = powf(1, step) * (1.0f / ((float)sima->custom_grid_subdiv));
+  const int flag = sima->flag;
+  for (int step = 0; step < SI_GRID_STEPS_LEN; step++) {
+    if (flag & SI_CUSTOM_GRID) {
+      grid_steps_x[step] = 1.0f / sima->custom_grid_subdiv[0];
+      grid_steps_y[step] = 1.0f / sima->custom_grid_subdiv[1];
     }
-  }
-  else {
-    for (int step = 0; step < SI_GRID_STEPS_LEN; step++) {
-      grid_steps[step] = powf(grid_dimension, step) *
-                         (1.0f / (powf(grid_dimension, SI_GRID_STEPS_LEN)));
+    else {
+      grid_steps_x[step] = powf(grid_dimension, step - SI_GRID_STEPS_LEN);
+      grid_steps_y[step] = powf(grid_dimension, step - SI_GRID_STEPS_LEN);
     }
   }
 }
diff --git a/source/blender/editors/space_image/space_image.c b/source/blender/editors/space_image/space_image.c
index 096ae4fd328..2b65267644a 100644
--- a/source/blender/editors/space_image/space_image.c
+++ b/source/blender/editors/space_image/space_image.c
@@ -112,7 +112,8 @@ static SpaceLink *image_create(const ScrArea *UNUSED(area), const Scene *UNUSED(
   simage->tile_grid_shape[0] = 1;
   simage->tile_grid_shape[1] = 1;
 
-  simage->custom_grid_subdiv = 10;
+  simage->custom_grid_subdiv[0] = 10;
+  simage->custom_grid_subdiv[1] = 10;
 
   /* header */
   region = MEM_callocN(sizeof(ARegion), "header for image");