Bugfix #28298

When I added DPI support in the UI, I added code that refreshes views for 2d
regions. These refreshes also happened on screen switches or file select, causing
header views (horizontal scrolled) to clear.

Now the code less intrusive, changing header views in fewer cases. 

This is a patch provided by Anthony Edlin. Thanks dude!

2 files changed, 9 insertions, 7 deletions

diff --git a/source/blender/editors/interface/view2d.c b/source/blender/editors/interface/view2d.c
index 559602b04c0..fb7a2615583 100644
--- a/source/blender/editors/interface/view2d.c
+++ b/source/blender/editors/interface/view2d.c
@@ -476,8 +476,14 @@ void UI_view2d_curRect_validate_resize(View2D *v2d, int resize)
 				if (winy < v2d->oldwiny) {
 					float temp = v2d->oldwiny - winy;
 					
-					cur->ymin += temp;
-					cur->ymax += temp;
+					if (v2d->align & V2D_ALIGN_NO_NEG_Y) {
+						cur->ymin -= temp;
+						cur->ymax -= temp;
+					}
+					else { /* Assume V2D_ALIGN_NO_POS_Y or combination */
+						cur->ymin += temp;
+						cur->ymax += temp;
+					}
 				}
 
 			}
diff --git a/source/blender/editors/screen/area.c b/source/blender/editors/screen/area.c
index eb08ba7d92e..c0f8da89306 100644
--- a/source/blender/editors/screen/area.c
+++ b/source/blender/editors/screen/area.c
@@ -1259,10 +1259,6 @@ void ED_area_initialize(wmWindowManager *wm, wmWindow *win, ScrArea *sa)
 			/* prevent uiblocks to run */
 			uiFreeBlocks(NULL, &ar->uiblocks);
 		}
-		
-		/* rechecks 2d matrix for header on dpi changing, do not do for other regions, it resets view && blocks view2d operator polls (ton) */
-		if (ar->regiontype == RGN_TYPE_HEADER)
-			ar->v2d.flag &= ~V2D_IS_INITIALISED;
 	}
 }
 
@@ -1775,7 +1771,7 @@ void ED_region_header(const bContext *C, ARegion *ar)
 	}
 
 	/* always as last  */
-	UI_view2d_totRect_set(&ar->v2d, maxco + UI_UNIT_X + 80, BLI_rctf_size_y(&ar->v2d.tot));
+	UI_view2d_totRect_set(&ar->v2d, maxco + UI_UNIT_X + 80, headery);
 
 	/* restore view matrix? */
 	UI_view2d_view_restore(C);