UI: better support for dynamically sized regions in topbar.

Dynamically sized regions in the topbar were flickering due to only updating
their size after redraws. Now there is an optional layout() callback for
all regions in an area to do UI layout first, then refresh the region layout,
and then do the actual drawing for each region.

Task T54753

1 files changed, 46 insertions, 17 deletions

diff --git a/source/blender/editors/interface/interface.c b/source/blender/editors/interface/interface.c
index eb69ccef2e4..99387a47670 100644
--- a/source/blender/editors/interface/interface.c
+++ b/source/blender/editors/interface/interface.c
@@ -224,6 +224,26 @@ void ui_region_to_window(const ARegion *ar, int *x, int *y)
 	*y += ar->winrct.ymin;
 }
 
+static void ui_update_window_matrix(const wmWindow *window, const ARegion *region, uiBlock *block)
+{
+	/* window matrix and aspect */
+	if (region && region->visible) {
+		/* Get projection matrix which includes View2D translation and zoom. */
+		gpuGetProjectionMatrix(block->winmat);
+		block->aspect = 2.0f / fabsf(region->winx * block->winmat[0][0]);
+	}
+	else {
+		/* No subwindow created yet, for menus for example, so we use the main
+		 * window instead, since buttons are created there anyway. */
+		int width = WM_window_pixels_x(window);
+		int height = WM_window_pixels_y(window);
+		rcti winrct = {0, width - 1, 0, height - 1};
+
+		wmGetProjectionMatrix(block->winmat, &winrct);
+		block->aspect = 2.0f / fabsf(width * block->winmat[0][0]);
+	}
+}
+
 /**
  * Popups will add a margin to #ARegion.winrct for shadow,
  * for interactivity (point-inside tests for eg), we want the winrct without the margin added.
@@ -2670,6 +2690,27 @@ void UI_block_free(const bContext *C, uiBlock *block)
 	MEM_freeN(block);
 }
 
+void UI_blocklist_update_window_matrix(const bContext *C, const ListBase *lb)
+{
+	ARegion *region = CTX_wm_region(C);
+	wmWindow *window = CTX_wm_window(C);
+
+	for (uiBlock *block = lb->first; block; block = block->next) {
+		if (block->active) {
+			ui_update_window_matrix(window, region, block);
+		}
+	}
+}
+
+void UI_blocklist_draw(const bContext *C, const ListBase *lb)
+{
+	for (uiBlock *block = lb->first; block; block = block->next) {
+		if (block->active) {
+			UI_block_draw(C, block);
+		}
+	}
+}
+
 /* can be called with C==NULL */
 void UI_blocklist_free(const bContext *C, ListBase *lb)
 {
@@ -2755,25 +2796,13 @@ uiBlock *UI_block_begin(const bContext *C, ARegion *region, const char *name, sh
 	if (region)
 		UI_block_region_set(block, region);
 
-	/* window matrix and aspect */
-	if (region && region->visible) {
-		gpuGetProjectionMatrix(block->winmat);
+	/* Set window matrix and aspect for region and OpenGL state. */
+	ui_update_window_matrix(window, region, block);
 
-		block->aspect = 2.0f / fabsf(region->winx * block->winmat[0][0]);
-	}
-	else {
-		/* no subwindow created yet, for menus for example, so we
-		 * use the main window instead, since buttons are created
-		 * there anyway */
-		int width = WM_window_pixels_x(window);
-		int height = WM_window_pixels_y(window);
-		rcti winrct = {0, width -1, 0, height - 1};
-
-		wmGetProjectionMatrix(block->winmat, &winrct);
-
-		block->aspect = 2.0f / fabsf(width * block->winmat[0][0]);
+	/* Tag as popup menu if not created within a region. */
+	if (!(region && region->visible)) {
 		block->auto_open = true;
-		block->flag |= UI_BLOCK_LOOP; /* tag as menu */
+		block->flag |= UI_BLOCK_LOOP;
 	}
 
 	return block;