Graphics Preferences

This tab allows you to control the layout and default size of IDL Graphics windows. You can also control IDL's default use of backing store and the size of the TrueType font cache. Note that the values set here are defaults; the values can be overridden when a graphics window is created.

Window layout / Windows Size Section

Specify the default width and height of IDL graphics windows in the Width and Height fields. Alternatively, you can specify that graphics windows have a default width and height of half the screen width and height by checking the 1/4 Screen Size checkbox.

Platform Differences

On Windows systems, you can specify that graphics windows should be created size-by-side, with no overlap by selecting the Tile radio button, or that they should be created overlapping by selecting the Cascade radio button. Select the Always On Top checkbox to ensure that graphics windows float above all other IDL windows.

Backing Store Section

When backing store is enabled, a copy of each Graphics window is kept in memory; the copy is used to refresh the window when it has been covered and uncovered. IDL's performance may increase when no backing store is used, since the amount of memory required to save files can affect the speed at which IDL will run. Settings in this section correspond to settings of the RETAIN keyword to the DEVICE procedure; see Backing Store for more information.

None (RETAIN = 0): Select this option to refrain from keeping a copy of the window. In some situations, disabling backing store may lead to an increase in IDL's performance.

System (RETAIN = 1): Select this option to request backing store from the windowing system. This is the default.

Bitmap / Pixmap (RETAIN = 2): Select this option to specify that IDL should maintain the backing store using its own memory.

Note

Backing Store

True Type Fonts Section

IDL saves TrueType fonts as a set of glyphs; each glyph represents the triangulation data for drawing one character. The Size of TrueType Font Cache (in glyphs) field allows you to set the number of glyphs to keep in cache memory; keeping glyphs in memory speeds drawing of fonts in IDL graphics windows. The default number of glyphs in cache memory is 256, roughly two TrueType font sets.

Enter the number of TrueType characters for which to save triangulation information. Saving the triangulation information for TrueType characters means that IDL will not have to calculate the polygons to draw the next time a character of the same font and size is rendered. Larger values will use more memory but can increase drawing speed if multiple fonts are used. The default is 256.

Default object graphics renderer / Graphics Attributes Section

IDL supports two methods of rendering object graphics: via a hardware graphics accelerator or via a software rendering package. Select Hardware rendering if your system has OpenGL graphics accelerator hardware. Select Software rendering otherwise.