Miscellaneous Operations for OS/2 Graphics - MIT/GNU Scheme 7.7.90+
Description: MIT/GNU Scheme 7.7.90+

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#### 17.11.5 Miscellaneous Operations for OS/2 Graphics

These operations allow you to: change the font used for drawing text in a graphics-device window; take a snapshot of a graphics-device window and return it as an image object; and draw multiple lines efficiently.

— operation on os2-graphics-device: set-font font-name

> This operation sets the font used for drawing text in the graphics-device window. Font-name is a string describing the font; this string is in the form "<point-size>.<family-name>", for example, `"10.Courier"`. You may specify any fixed-pitch font family, in any point size that is supported for that font family. This includes both image fonts and outline fonts.

— operation on os2-graphics-device: capture-image x-left y-bottom x-right y-top

> This operation creates and returns an image that contains part of the client area of the graphics-device window. The portion of the client area that is selected is specified by the four coordinate arguments, which are given in the current virtual coordinates for the device. See Images, for more information about manipulating images.

— operation on os2-graphics-device: draw-lines xv yv

> This operation draws multiple disjoint lines; it is like multiple calls to `graphics-draw-line` but much faster. The arguments xv and yv are vectors of coordinates; these vectors must be the same length, and the length must be a multiple of two. The contents of the vectors are alternating start/end pairs. For example, the following are equivalent:

>               (graphics-draw-line device xs ys xe ye)
>               (graphics-operation device 'draw-lines
>                                   (vector xs xe)
>                                   (vector ys ye))