Open Viewport

Creates a viewport leading to another canvas.

Syntax

Open Viewport canvas,x1,y1 to x2,y2

Description

This command creates a viewport which leads to canvas.

The viewport is drawn on the screen at co-ordinates x1,y1 to x2,y2.

A viewport is an area of the screen which can be 'seen through' to the canvas below it. All sprites, buttons and backgrounds that are in the canvas are copied to the screen inside the viewport.

Every time Draw Frame is called then the viewport is updated just like the rest of the screen.

Note: Once a viewport has been drawn to the screen the contents of that area of canvas 0 are overwritten with the contents of the viewport.

The canvas underneath the viewport can be larger than the display area. In this case, only a certain area of the canvas is drawn to the screen. This can be used to produce scrolling effects (see Set Viewport Offset).

A viewport can be removed from the display with the function Close Viewport.


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