►The Racket Graphical Interface Toolkit
▼6 Snip and Style Classes
On this page:
make-object
equal-hash-code-of
equal-secondary-hash-code-of
get-bitmap
get-bitmap-mask
get-filename
get-filetype
load-file
other-equal-to?
resize
set-bitmap
set-offset
Inherited methods:
from snip%
adjust-cursor
blink-caret
can-do-edit-operation?
copy
do-edit-operation
draw
equal-to?
find-scroll-step
get-admin
get-count
get-extent
get-flags
get-num-scroll-steps
get-scroll-step-offset
get-snipclass
get-style
get-text
get-text!
is-owned?
match?
merge-with
next
on-char
on-event
on-goodbye-event
own-caret
partial-offset
previous
release-from-owner
set-admin
set-count
set-flags
set-snipclass
set-style
set-unmodified
size-cache-invalid
split
write
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class

image-snip% : class?

  superclass: snip%

An image-snip% is a snip that can display bitmap images (usually loaded from a file). When the image file cannot be found, a box containing an “X” is drawn.

constructor

(make-object image-snip% [file 
  kind 
  relative-path? 
  inline? 
  backing-scale]) 
 → (is-a?/c image-snip%)
  file : (or/c path-string? input-port? #f) = #f
  kind : 
(or/c 'unknown 'unknown/mask 'unknown/alpha
      'gif 'gif/mask 'gif/alpha
      'jpeg 'png 'png/mask 'png/alpha
      'xbm 'xpm 'bmp 'pict)
 = 'unknown
  relative-path? : any/c = #f
  inline? : any/c = #t
  backing-scale : (>/c 0.0) = 1.0
(make-object image-snip% bitmap [mask]) → (is-a?/c image-snip%)
  bitmap : (is-a?/c bitmap%)
  mask : (or/c (is-a?/c bitmap%) #f) = #f
Creates an image snip, loading the image file if specified (see also load-file), or using the given bitmap.

Changed in version 1.1 of package snip-lib: Added the backing-scale argument.

method

(send an-image-snip equal-hash-code-of hash-code)

 → exact-integer?
  hash-code : (any/c . -> . exact-integer?)
Returns an integer that can be used as a equal?-based hash code for an-image-snip (using the same notion of equal? as other-equal-to?).

See also equal<%>.

method

(send an-image-snip equal-secondary-hash-code-of hash-code)

 → exact-integer?
  hash-code : (any/c . -> . exact-integer?)
Returns an integer that can be used as a equal?-based secondary hash code for an-image-snip (using the same notion of equal? as other-equal-to?).

See also equal<%>.

method

(send an-image-snip get-bitmap) → (or/c (is-a?/c bitmap%) #f)

Returns the bitmap that is displayed by the snip, whether set through set-bitmap or load-file. If no bitmap is displayed, the result is #f.

method

(send an-image-snip get-bitmap-mask)

 → (or/c (is-a?/c bitmap%) #f)
Returns the mask bitmap that is used for displaying by the snip, if one was installed with set-bitmap. If no mask is used, the result is #f.

method

(send an-image-snip get-filename [relative-path])

 → (or/c path-string? #f)
  relative-path : (or/c (box/c any/c) #f) = #f
Returns the name of the currently loaded, non-inlined file, or #f if a file is not loaded or if a file was loaded with inlining (the default).

The relative-path box is filled with #t if the loaded file’s path is relative to the owning editor’s path, unless relative-path is #f.

method

(send an-image-snip get-filetype)

 → 
(or/c 'unknown 'unknown/mask 'unknown/alpha
      'gif 'gif/mask 'gif/alpha
      'jpeg 'png 'png/mask 'png/alpha
      'xbm 'xpm 'bmp 'pict)
Returns the kind used to load the currently loaded, non-inlined file, or 'unknown if a file is not loaded or if a file was loaded with inlining (the default).

method

(send an-image-snip load-file file    
  [kind    
  relative-path?    
  inline?    
  backing-scale]) → void?
  file : (or/c path-string? input-port? #f)
  kind : 
(or/c 'unknown 'unknown/mask 'unknown/alpha
      'gif 'gif/mask 'gif/alpha
      'jpeg 'png 'png/mask 'png/alpha
      'xbm 'xpm 'bmp 'pict)
 = 'unknown
  relative-path? : any/c = #f
  inline? : any/c = #t
  backing-scale : (>/c 0.0) = 1.0
Loads the file by passing file and kind to load-file in bitmap%. If a bitmap had previously been specified with set-bitmap, that bitmap (and mask) will no longer be used. If file is #f, then the current image is cleared.

When 'unknown/mask, 'gif/mask, or 'png/mask is specified and the loaded bitmap object includes a mask (see get-loaded-mask), the mask is used for drawing the bitmap (see draw-bitmap). The 'unknown/alpha, 'gif/alpha, or 'png/alpha variants are recommended, however.

If relative-path? is not #f and file is a relative path, then the file will be read using the path of the owning editor’s filename. If the image is not inlined, it will be saved as a relative pathname.

If inline? is not #f, the image data will be saved directly to the file or clipboard when the image is saved or copied (preserving the bitmap’s mask, if any). The source filename and kind is no longer relevant.

Changed in version 1.1 of package snip-lib: Added the backing-scale argument.

method

(send an-image-snip other-equal-to? snip    
  equal?) → boolean?
  snip : (is-a?/c snip%)
  equal? : (any/c any/c . -> . boolean?)
Returns #t if an-image-snip and snip both have bitmaps and the bitmaps are the same. If either has a mask bitmap with the same dimensions as the main bitmap, then the masks must be the same (or if only one mask is present, it must correspond to a solid mask).

The given equal? function (for recursive comparisons) is not used.

method

(send an-image-snip resize w h) → boolean?

  w : (and/c real? (not/c negative?))
  h : (and/c real? (not/c negative?))
Overrides resize in snip%.
The bitmap will be cropped to fit in the given dimensions.

method

(send an-image-snip set-bitmap bm [mask]) → void?

  bm : (is-a?/c bitmap%)
  mask : (or/c (is-a?/c bitmap%) #f) = #f
Sets the bitmap that is displayed by the snip.

An optional mask is used when drawing the bitmap (see draw-bitmap), but supplying the mask directly is deprecated. If no mask is supplied but the bitmap’s get-loaded-mask method produces a bitmap of the same dimensions, it is used as the mask; furthermore, such a mask is saved with the snip when it is saved to a file or copied (whereas a directly supplied mask is not saved). Typically, however, bm instead should have an alpha channel instead of a separate mask bitmap.

method

(send an-image-snip set-offset dx dy) → void?

  dx : real?
  dy : real?
Sets a graphical offset for the bitmap within the image snip.

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