The paint event handler provides you with a parameter containing the Graphics object that you can draw into. In most situations you will use the Paint event handler to draw something in the Canvas.
#Xojo canvas how to
See the Canvas control entry in the Language Reference for an example of how to do this. However, it is easy to simulate a focus ring by manually drawing it in the Paint event handler. There is no visual indicator of focus that works automatically. On Windows and Linux, the AllowFocusRing property has no effect. If the AllowFocus and AllFocusRing properties are set to True, the Canvas control indicates focus on macOS by drawing a border around the control.
#Xojo canvas code
If AllowTabs is on, the Canvas control detects the Tab key as if it were any other key and allows your code to detect and respond to the Tab key. The next control in the entry order gets the focus. 1The Scroll & Zoom Canvas has been optimized for ultra-fast scrolling and zooming.
If AllowTabs is off, pressing Tab causes the Canvas control to lose the focus. The Canvas control also has an AllowTabs property that indicates whether pressing Tab selects the next control in the window or sends the Tab keystroke to the Canvas control for processing. This can be done either in code or in the Inspector. In order for a Canvas control to receive the focus, you must set the AllowFocusRing property to True. Unlike other controls that can get the focus, the ability of a Canvas to accept the focus is turned off by default. For example, you can use the Canvas to simulate controls that don’t get the focus on macOS, such as buttons and pop-up menus. Since the Canvas control can get the focus, you can use it to create custom controls of any type that can get the focus. Scroll - Use the Scroll method to scroll the contents of the Canvas.
You can alternatively tell it to refresh only a portion of the Canvas. Refresh - Call this method to tell the operating system to redraw the Canvas when it is doing other redrawing or immediately.
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