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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This is easily done with the statement: These keywords control the position of IDL plots on the page. The following example writes a bit ivl, interleaved over the 3rd dimension, to a PostScript file: It sets the read-only system variable!
PostScript is a programming language designed to convey a description of a page containing text and graphics. You have more options under Linux, but your best bet is to use a program called “gv.
A true-color image consists of an array with three dimensions, one of which has a size of three, containing the three color components. Image Background Color Images that are displayed with a black background on a monitor frequently look better if the background is changed to white when displayed with PostScript. True-Color Images A true-color image consists of an array with three set_poot, one of which has a size of three, containing the three color components.
Color PostScript If you have a color PostScript device you can enable the use of color with the statement: Back to Index Next Tutorial. 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.
IDL Tutorial 2 : Plots and Output Files for Making Hardcopies
Color Images To obtain adequate resolution, the device coordinate system used for PostScript output is expressed in units of 0. For example, to create and load a color table with four seh_plot, black, red, green and blue: Generating Hardcopy of Plots There are many different ways to produce plots in a format other than onto the IDL graphics window.
Suppose this script is called plotmydata. Keyword parameters control how the color tables are transferred to the newly selected graphics device.
It was produced with the following IDL statements: Images that are displayed with a black background on a monitor frequently look better if the background is changed to white when displayed with PostScript. The resulting file produces a set seet_plot plots as shown in Multiple plots on a single page produced by setting the!
Drawing text or graphics with a color index of 0 results in black, 1 in red, 2 in ste_plot, and 3 in blue. MULTI system variable described in more detail in.
True-color images are also routed through the color tables.
Color output or direct color separations can be produced with color PostScript. 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. As an example, suppose you have an image that is narrow and tall that, when TV’ed to an IDL window, fills only a small portion of the plotting window.
It may be considered as three two dimensional images, one each for the red, green and blue components. TV, array ; Write the image to the file.
This is the preferred method if you are displaying graphics and each color index is explicitly loaded. Run your plotting script.
Great FTP software, too! By convention the first color is always red, the second green, and the last is blue. As with black and white PostScript, images may be output with 1, 2, 4, or 8 bits, yielding 1, 2, 16, or possible colors.
This happens because IDL moves the origin of the plot before rotating the PostScript coordinate system degrees clockwise for the landscape plot. A PDF file can be made in this way directly from a cgWindow. It demonstrates some of the three-dimensional plotting capabilities of IDL.
Creating PDF Files in IDL
The following example writes a bit image, interleaved over the 3rd dimension, to a PostScript file:. A pseudo-color image is a two dimensional image, each pixel of which is used to index the color table, thereby obtaining an RGB value for each possible pixel value. If the image column size is not an exact multiple, extra pixels with a value of are output at the end of each row. To put multiple plots on the same PostScript page, use the!
The page on the right shows an IDL plot printed in “landscape” orientation. The assumption is that you are on a Windows-based machine, but I’ll include some info to help you plot from Linux, below.
This make automatic generation of PDF files problematic. Jdl page on the left shows an IDL plot set_plor in wet_plot orientation. It sets the default color! Setting the output color index to 0, the default when PostScript output is selected, writes black. This section shows how to generate IDL PostScript graphics so that they can be inserted into other documents. Assuming that the previously-selected device’s color table contains M elements, and the new device’s color table contains N elements, then the minimum of M and N elements are loaded.
A PDF document with my graphics was created! Seet_plot offset is also taken relative to the lower left-hand corner of the page when viewed in portrait orientation. To direct graphics output to a PostScript se_plot, issue the command:.
As with most display devices, color indices range from seet_plot to The procedure comprises the following steps: The default is to do nothing.
To direct graphics output to a PostScript file, issue the command: Note that if you have Adobe Acrobat, you can also use the Adobe PDF printer that is installed with Acrobat to accomplish the same thing.
The case of Device is ignored by IDL.