View Graphics

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View (Graphics)

Sets the rectangle that drawing is clipped to, or resets it to the whole screen.

Syntax

View
View ( x1, y1 )-( x2, y2 ) [ [, fill_color ] [, border_color ] ]
View Screen ( x1, y1 )-( x2, y2 ) [ [, fill_color ] [, border_color ] ]

Parameters

• x1
• y1
• x2
• y2
• fill_color
• border_color

Description

The viewport, or clipping region, is a rectangular area of the graphics screen, outside of which no graphics drawing will be done. That is, only graphics drawing done within this area will be shown. A graphics screen must be created with Screen (Graphics) or ScreenRes before calling View or View Screen.

The first statement (View) sets the viewport to encompass the entire screen, which is the default viewport for a new graphics screen.

The second and third statements (View parameters and View Screen parameters) both allow a new viewport to be defined. The indicated effects for each parameter only occur if that parameter is specified:

Remarks

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

Examples

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)

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Category: Screen Functions
Kind: keyword

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Reproduced from the FreeBASIC Wiki Manual under the GNU Free Documentation License 1.3 — with no Invariant Sections, no Front-Cover Texts and no Back-Cover Texts. Copyright © the FreeBASIC project and wiki contributors. See License.