int CanvasClear (int panelHandle, int controlID, Rect rect);
Restores the specified rectangular area of a canvas control to the background color of the canvas control.
You can set the background color of the canvas control through the ATTR_PICT_BGCOLOR attribute.
Unlike other canvas drawing operations, CanvasClear can clear the canvas control beyond the canvas clipping rectangle.
Input | ||
Name | Type | Description |
panelHandle | integer | Specifier for a particular panel that is currently in memory. You obtain this handle from LoadPanel, NewPanel, or DuplicatePanel. |
controlID | integer | The defined constant, located in the .uir header file, that you assigned to the control in the User Interface Editor, or the ID returned by NewCtrl or DuplicateCtrl. |
rect | Rect | Rect structure that specifyies the location and size of the rectangle to clear. Use VAL_ENTIRE_OBJECT to specify the entire canvas. The Rect structure is defined as follows: typedef struct { int top; int left; int height; int width; } Rect; You can create a Rect without having to declare a variable by using the following function: Rect MakeRect (int top, int left, int height, int width); ExampleCanvasClear (panelHandle, controlID, VAL_ENTIRE_OBJECT); |
Name | Type | Description | ||||
status | integer | Return value indicating whether the function was successful. A negative number indicates that an error occurred.
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