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HP2XX, A HP-GL Converter

2.8 Preview

Preview mode is hp2xx's default. Its use prior to all other conversions is recommended since it offers a good impression of your final results. Functionally it is also a raster mode.

Depending on your hardware and operating system platform, hp2xx uses one of a variety of preview modules. On GUIs, a window containing the graphics will pop up, while on other systems the whole screen may be used for preview. You can control the position of a preview window via options `-o' and `-O' in a natural way. In full-screen previews, unused spaces are padded to the right and bottom with background color.

Since there is no way for hp2xx to predict the actual size and resolution of your preview device, e.g., screen, you may have to gauge hp2xx's preview mode (using options `-whdD'). For example, if your device effectively works at 86 DPI and offers an active area of 24 by 18 cm,

hp2xx -d86 -w240 -h180 foo.hp

will make maximum use of your screen area and give you correct sizes. Since a single gauge will do for all future calls, you'll probably want to create some one-line batch file for invoking hp2xx in preview mode, correctly gauged for your screen.

Depending on page offsets and the selected sizes and resolutions, a preview may not fit on your screen. In that case, some preview modules simply clip the picture; others give a warning but let you continue (DOS), and others simply terminate.

The X11 viewer allows to pan the visible area using mouse button one (which usually corresponds to the left button), and supports one level of zoom around the current cursor position, selectable with button two (middle button, or right button on two-button mice).

DOS users: Most VGA cards offer high-resolution modes (SVGAs). Unfortunately, there is no software standard for these modes. hp2xx lets you utilize these modes anyway with just a little help from you. Tell hp2xx the so-called mode byte of your favorite hi-res mode via option `-V num'. Since hp2xx issues only standard BIOS calls for mode switching, setting of color look-up table entries, and pixel drawing, chances are good that your VGA card's hi-res modes will work!

WARNING: You can damage your hardware by specifying inappropriate VGA modes! Generally you'll need a monitor which can sync on the horizontal frequency of the selected VGA hi-res mode, e.g., a multi-scan monitor. In case of doubt, switch off your monitor immediately!!