Tk\_ImageChanged(3) Tk Library Procedures Tk\_ImageChanged(3)

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# [NAME](#NAME)

Tk\_ImageChanged - notify widgets that image needs to be redrawn

# [SYNOPSIS](#SYNOPSIS)

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#include <tk.h>

Tk_ImageChanged(model, x, y, width, height, imageWidth, imageHeight)
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# [ARGUMENTS](#ARGUMENTS)

Tk\_ImageModel *model* (in)

Token for image, which was passed to image's *createProc* when the image was created.

int *x* (in)

X-coordinate of upper-left corner of region that needs redisplay (measured from upper-left corner of image).

int *y* (in)

Y-coordinate of upper-left corner of region that needs redisplay (measured from upper-left corner of image).

int *width* (in)

Width of region that needs to be redrawn, in pixels.

int *height* (in)

Height of region that needs to be redrawn, in pixels.

int *imageWidth* (in)

Current width of image, in pixels.

int *imageHeight* (in)

Current height of image, in pixels.

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# [DESCRIPTION](#DESCRIPTION)

An image manager calls **Tk\_ImageChanged** for an image whenever anything happens that requires the image to be redrawn. As a result of calling **Tk\_ImageChanged**, any widgets using the image are notified so that they can redisplay themselves appropriately. The *model* argument identifies the image, and *x*, *y*, *width*, and *height* specify a rectangular region within the image that needs to be redrawn. *imageWidth* and *imageHeight* specify the image'[s (new)](/man/os/tk/s.new) size.

An image manager should call **Tk\_ImageChanged** during its *createProc* to specify the image's initial size and to force redisplay if there are existing instances for the image. If any of the pixel values in the image should change later on, **Tk\_ImageChanged** should be called again with *x*, *y*, *width*, and *height* values that cover all the pixels that changed. If the size of the image should change, then **Tk\_ImageChanged** must be called to indicate the new size, even if no pixels need to be redisplayed.

# [SEE ALSO](#SEE_ALSO)

Tk\_CreateImageType

# [KEYWORDS](#KEYWORDS)

images, redisplay, image size changes

4.0 Tk

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Document: Tk_ImageChanged(3) from tk 9.1.0-r0 (Chainguard OS)
Source: https://downloads.sourceforge.net/sourceforge/tcl/tk9.1.0-src.tar.gz