View (Graphics)
Sets new physical coordinate mapping and clipping region
Syntax
`
View
View ( x1, y1 )-( x2, y2 ) [ [, fill_color ] [, border_color ] ]
View Screen ( x1, y1 )-( x2, y2 ) [ [, fill_color ] [, border_color ] ]
`
Parameters
`x1` `As Integer`, `y1` `As Integer`
The horizontal and vertical offsets, in pixels, of one corner of the viewport relative to the top-left corner of the screen.
`x2` `As Integer`, `y2` `As Integer`
The horizontal and vertical offsets, in pixels, of the opposite corner of the viewport relative to the top-left corner of the screen.
`fill_color` `As UInteger`
The color to fill the new viewport.
`border_color` `As UInteger`
The color of the border to draw around the new viewport.
Description
The viewport, or clipping region, is a rectangular area of the graphics screen, outside of which no drawing will be done. That is, only drawing done within this area will be shown. A graphics screen must be created with `Screen` or `ScreenRes` before calling `View` or `View Screen`.
The first statement sets the viewport to encompass the entire screen, which is the default viewport for a new graphics screen.
The second and third statements both allow a new viewport to be defined. The corners of the viewport are specified by the `x1`, `y1`, `x2` and `y2` parameters. `fill_color` and `border_color` are both in the format accepted by `Color`. The indicated effects for each parameter only occur if that parameter is specified.
The second statement modifies the coordinate mapping of the graphics screen such that coordinates specified for drawing statements and procedures are relative to the top-left corner of the viewport.
The third statement modifies the coordinate mapping of the graphics screen such that coordinates specified for drawing statements and procedures are relative to the top-left corner of the screen.
Example
`
Screen 12
Dim ip As Any Ptr
Dim As Integer x, y
'simple sprite
ip = ImageCreate(64,64)
For y = 0 To 63
For x = 0 To 63
PSet ip, (x, y), (x\4) Xor (y\4)
Next x
Next y
'viewport with blue border
Line (215,135)-(425,345), 1, bf
View (220,140)-(420,340)
'move sprite around the viewport
Do
x = 100*Sin(Timer*2.0)+50
y = 100*Sin(Timer*2.7)+50
ScreenSync
ScreenLock
'clear viewport and put image
Cls 1
Put (x, y), ip, PSet
ScreenUnlock
Loop While Inkey = ""
ImageDestroy(ip)
`
Differences from QB

- QBASIC preserves the `WINDOW` coordinate mapping after subsequent calls to `VIEW`.
- FreeBASIC's current behavior is to preserve the `WINDOW` coordinates after calls to `VIEW`, or when working on images, meaning that the coordinate mapping may undergo scaling/translations if the viewport changes. (If a `WINDOW` hasn't been set, there is no coordinate mapping, and so it doesn't change after calls to `VIEW`.) The behavior may change in future, but consistent behavior can be assured over inconstent viewport coordinates by re-calling `WINDOW` whenever you change the `VIEW`.

See also

- `View Print`
- `Screen (Graphics)`
- `Window`
- `PMap`