CanvasDrawOval
int CanvasDrawOval (int panelHandle, int controlID, Rect rectangle, int drawMode);
Purpose
Draws an oval on the canvas control within the specified rectangle.
CanvasDrawOval draws the frame of the oval using the current value of the following attributes:
ATTR_PEN_COLOR
ATTR_PEN_MODE
ATTR_PEN_WIDTH
ATTR_PEN_STYLE (ignored when pen width is greater than one)
CanvasDrawOval draws the interior of the oval using the current value of the following attributes:
ATTR_PEN_FILL_COLOR
ATTR_PEN_MODE
ATTR_PEN_PATTERN
Supported Controls
You can use CanvasDrawOval with canvas controls.
Parameters
| Input | ||
| Name | Type | Description |
| panelHandle | int | Specifier for a particular panel that is currently in memory. You can obtain this handle from functions such as LoadPanel and NewPanel. |
| controlID | int | 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 functions such as NewCtrl and DuplicateCtrl. |
| rectangle | Rect | Rect structure specifying the location and size of the rectangle within which to draw the oval. 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); ExampleCanvasDrawOval (panelHandle, controlID, MakeRect(20,30,150,200), VAL_DRAW_FRAME); |
| drawMode | int | Specifies whether to draw the oval frame, or interior, or both. The following lists the valid values. VAL_DRAW_FRAME VAL_DRAW_INTERIOR VAL_DRAW_FRAME_AND_INTERIOR |
Return Value
| Name | Type | Description |
| status | int | Return value indicating whether the function was successful. A negative number indicates that an error occurred. |
Additional Information
Library: User Interface Library
Include file: userint.h
LabWindows/CVI compatibility: LabWindows/CVI 4.0 and later
Example
Refer to userint\canvas.cws for an example of using the CanvasDrawOval function.