IDL Tutorial 2: Plots and Output Files for Making Hardcopies .. Hence, you need to first start the PS device using the set_plot command, and then use the. SET_PLOT, ‘PS’. This causes IDL to use the PostScript driver for producing graphical output. Once the PostScript driver is enabled via SET_PLOT, the DEVICE. IDL treats the screen as one device and a postscript file (which you can print) as another. You can switch devices with the set_plot command.
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For example, the following lines of code create a PostScript file, multi. After installing Ghostscript, creating a PDF file can be as simple as this. To pass the RGB pixel values without change, load the red, green and blue color tables with a ramp with a slope of 1.
The first element of! This is straightforward if both devices have the same number of color indices.
True-color images are also routed through the color tables. On Windows and UNIX computers, excluding Macintosh computers, the conversion is done with Ghostscripta free, easily obtained and installed software package.
Great FTP software, too! MULTI system variable described in more detail in. Here is a set of commands to generate an encapsulated postscript file. MULTI is a counter that reports how many plots remain on the page. The user is required to select the printer manually from the printer dialog. Be careful when switching set_pplot as the number of color indices frequently differs between devices. This method works best when displaying images with continuous color ranges.
IDL Graphics Devices
MULTI is a 5-element integer array that controls the number of rows and columns of plots to make on a page or in a graphics window. Department of Physics and Astronomy. The procedure comprises the following steps: Color PostScript If you have a color PostScript device you can enable the use of color with the statement: Polygon Filling Example illustrates polygon filling.
The page on the left shows an IDL plot printed in “portrait” orientation. This happens because IDL moves the origin of the plot before rotating the PostScript coordinate system degrees clockwise for the landscape plot. As with most display devices, color indices range from 0 il It also provides several examples of how the PostScript graphics device is used. For example, to create and load a color table with four elements, black, red, green and blue: Now, under Windows, the easiest way to view and print the file is to use GSView, which is probably not installed on the computer you’re using.
Text and graphic color indices are translated to RGB by dividing the red, green and blue color table values by A est_plot index of writes white which is invisible on white paper. TVLCT, [0,0,0], [0,0,0], [0,0,0,] Drawing text or graphics with a color index of 0 results in black, 1 in red, 2 in green, and 3 in blue. Sometimes, however, the default bounding box is inappropriate for the image being displayed.
In this case, the same image is reproduced four times. A value of 1 specifies pixel interleaving, 2 is row interleaving, and 3 is image interleaving. Set this keyword to copy the device’s color table from the internal color table, preserving the current color mapping. This is easily done with the statement:. If you have a color PostScript device you can enable the use of color with the statement:.
IDL Tutorial 2 : Plots and Output Files for Making Hardcopies
It may be considered as three two dimensional images, one each for the red, green and set_plott components. In addition, images are either pseudo-color or true-color. The assumption is that you are on a Windows-based machine, but I’ll include some info to help you plot from Linux, below.
As an example, suppose you have an image that is narrow and tall that, when TV’ed to an IDL window, set_ploy only a small portion of the plotting window.
The following example writes a bit image, interleaved over the 3rd dimension, to a PostScript file: Set this keyword to indicate that the current contents of the internal color table should be interpolated to cover the range of the newly-selected device. Any routines that rely on data coordinates should not be called set_pllt a new data coordinate system has been established.
A scalar string containing the name of the device to use. To direct udl output to set_pot PostScript file, issue the command:. It demonstrates some of the three-dimensional plotting capabilities of IDL. PostScript is a programming language designed to convey a description of a page containing text and graphics. Back to Index Next Tutorial. This make automatic generation of PDF files problematic.
This is easily done with the statement: If the new device has less colors than the old, not all the colors are saved.