add region resize topright and bottomleft

Author: jcupitt

TODO

@@ -1,3 +1,7 @@
+- add snap for region resize and arrow end move
+
+- during region move or resze, the cursor changes back to a pointer
+
 - row range select breaks after "duplicate"
 
 	shift and ctrl click stop affecting select

src/regionview.c

@@ -774,30 +774,40 @@ regionview_resize(Regionview *regionview, guint modifiers,
 		imageui_snap_rect(imageui, our_area, our_area);
 		break;
 
-	case REGIONVIEW_RESIZE_RIGHT:
+	case REGIONVIEW_RESIZE_TOPLEFT:
+		our_area->left = x + start_area->left;
+		our_area->top = y + start_area->top;
+		break;
+
+	case REGIONVIEW_RESIZE_TOP:
+		our_area->top = y + start_area->top;
+		break;
+
+	case REGIONVIEW_RESIZE_TOPRIGHT:
+		our_area->top = y + start_area->top;
 		our_area->width = x + VIPS_RECT_RIGHT(start_area) - start_area->left;
 		break;
 
-	case REGIONVIEW_RESIZE_BOTTOM:
-		our_area->height = y + VIPS_RECT_BOTTOM(start_area) - start_area->top;
+	case REGIONVIEW_RESIZE_RIGHT:
+		our_area->width = x + VIPS_RECT_RIGHT(start_area) - start_area->left;
 		break;
 
 	case REGIONVIEW_RESIZE_BOTTOMRIGHT:
 		our_area->width = x + VIPS_RECT_RIGHT(start_area) - start_area->left;
 		our_area->height = y + VIPS_RECT_BOTTOM(start_area) - start_area->top;
 		break;
 
-	case REGIONVIEW_RESIZE_LEFT:
-		our_area->left = x + start_area->left;
+	case REGIONVIEW_RESIZE_BOTTOM:
+		our_area->height = y + VIPS_RECT_BOTTOM(start_area) - start_area->top;
 		break;
 
-	case REGIONVIEW_RESIZE_TOP:
-		our_area->top = y + start_area->top;
+	case REGIONVIEW_RESIZE_BOTTOMLEFT:
+		our_area->left = x + start_area->left;
+		our_area->height = y + VIPS_RECT_BOTTOM(start_area) - start_area->top;
 		break;
 
-	case REGIONVIEW_RESIZE_TOPLEFT:
+	case REGIONVIEW_RESIZE_LEFT:
 		our_area->left = x + start_area->left;
-		our_area->top = y + start_area->top;
 		break;
 
 	default:
@@ -840,6 +850,22 @@ regionview_resize(Regionview *regionview, guint modifiers,
 			our_area->height = VIPS_RECT_BOTTOM(start_area) - our_area->top;
 			break;
 
+		case REGIONVIEW_RESIZE_TOPRIGHT:
+			our_area->top =
+				VIPS_CLIP(0, our_area->top, VIPS_RECT_BOTTOM(start_area) - 1);
+			our_area->width =
+				VIPS_CLIP(1, our_area->width, width - start_area->left);
+			our_area->height = VIPS_RECT_BOTTOM(start_area) - our_area->top;
+			break;
+
+		case REGIONVIEW_RESIZE_BOTTOMLEFT:
+			our_area->left =
+				VIPS_CLIP(0, our_area->left, VIPS_RECT_RIGHT(start_area) - 1);
+			our_area->height =
+				VIPS_CLIP(1, our_area->height, height - start_area->top);
+			our_area->width = VIPS_RECT_RIGHT(start_area) - our_area->left;
+			break;
+
 		default:
 			break;
 		}