113 lines
4.3 KiB
Racket
113 lines
4.3 KiB
Racket
#lang scribble/doc
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@(require "common.rkt")
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@title{Global Graphics}
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@defproc[(flush-display)
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void?]{
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Flushes canvas offscreen drawing and other updates onto the
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screen.
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Normally, drawing is automatically flushed to the screen. Use
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@racket[flush-display] sparingly to force updates to the screen when
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other actions depend on updating the display.}
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@defproc[(get-display-backing-scale [#:monitor monitor exact-nonnegative-integer? 0])
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(or/c (>/c 0.0) #f)]{
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Returns the number of pixels that correspond to one drawing unit on a
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monitor. The result is normally @racket[1.0], but it is @racket[2.0]
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on Mac OS X in Retina display mode, and on Windows it can be a value
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such as @racket[1.25], @racket[1.5], or @racket[2.0] when the operating-system
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scale for text is changed. See also @secref["display-resolution"].
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On Mac OS X, the result can change at any time. See also
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@xmethod[top-level-window<%> display-changed].
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If @racket[monitor] is not less than the current number of available
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monitors (which can change at any time), the is @racket[#f]. See also
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@xmethod[top-level-window<%> display-changed].
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@history[#:changed "1.2" @elem{Added backing-scale support on Windows.}]}
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@defproc[(get-display-count) exact-positive-integer?]{
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Returns the number of monitors currently active.
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On Windows and Mac OS X, the result can change at any time.
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See also @xmethod[top-level-window<%> display-changed].}
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@defproc[(get-display-depth)
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exact-nonnegative-integer?]{
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Returns the depth of the main display (a value of 1 denotes a monochrome display).
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}
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@defproc[(get-display-left-top-inset [avoid-bars? any/c #f]
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[#:monitor monitor exact-nonnegative-integer? 0])
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(values (if (= monitor 0)
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exact-nonnegative-integer?
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(or/c exact-nonnegative-integer? #f))
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(if (= monitor 0)
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exact-nonnegative-integer?
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(or/c exact-nonnegative-integer? #f)))]{
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When the optional argument is @racket[#f] (the default), this function
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returns the offset of @racket[monitor]'s origin from the
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top-left of the physical monitor. For @racket[monitor] @racket[0], on Unix and Windows, the result is
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always @racket[0] and @racket[0]; on Mac OS X, the result is
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@racket[0] and the height of the menu bar. To position a frame
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at a given @racket[monitor]'s top-left corner, use the negated results from
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@racket[get-display-left-top-inset] as the frame's position.
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When the optional @racket[avoid-bars?] argument is true, for @racket[monitor]
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@racket[0], @racket[get-display-left-top-inset] function returns the
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amount space at the left and top of the monitor that is occupied by
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the task bar (Windows) or menu bar and dock (Mac OS X). On Unix, for
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monitor @racket[0], the result is always @racket[0] and @racket[0].
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For monitors other than @racket[0], @racket[avoid-bars?] has no effect.
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If @racket[monitor] is not less than the current number of available
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monitors (which can change at any time), the results are @racket[#f]
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and @racket[#f]. See also @xmethod[top-level-window<%> display-changed].
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See also @secref["display-resolution"].}
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@defproc[(get-display-size [full-screen? any/c #f]
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[#:monitor monitor exact-nonnegative-integer? 0])
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(values (if (= monitor 0)
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exact-nonnegative-integer?
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(or/c exact-nonnegative-integer? #f))
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(if (= monitor 0)
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exact-nonnegative-integer?
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(or/c exact-nonnegative-integer? #f)))]{
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@index["screen resolution"]{Gets} the physical size of the specified @racket[monitor] in
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pixels. On Windows, this size does not include the task bar by
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default. On Mac OS X, this size does not include the menu bar or
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dock area by default.
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On Windows and Mac OS X, if the optional argument is true and @racket[monitor] is @racket[0], then
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the task bar, menu bar, and dock area are included in the result.
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If @racket[monitor] is not less than the current number of available
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monitors (which can change at any time), the results are @racket[#f]
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and @racket[#f]. See also @xmethod[top-level-window<%> display-changed].
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See also @secref["display-resolution"].}
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@defproc[(is-color-display?)
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boolean?]{
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Returns @racket[#t] if the main display has color, @racket[#f]
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otherwise.
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}
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