Idl transparent polygon postscript driver

I notice that most idl graphics windows have black backgrounds with the graphics draw in white. How to create a transparent shadow on the postscript device. Perhaps this article will help you to extract the vertices of the polygon looks like youll have to cough up a bit of cash for the routine he uses to do so. This makes it extremely difficult to write idl programs that work both on the display and and in a postscript device. The choice depends upon the architecture of the cpu and the compiler. This means that the postscript language creates all of the print data and does not rely on the printer for print data.

Drawing a transparent polygon on a line plot in idl. The default postscript settings are given in the following table. Generally, for postscript printers, you will not need a driver, as all applications produce postscript. R latex, eps graphics and transparent colors grokbase. An integer between 0 and 100 that specifies the percent transparency of the polygon. Most of the people using idl this way did not realize they had missed the color memo until they observed other idl programmers working in completely different ways. How can i get the pixel data corresponding to a shapefile. Prints screen or image array onto a postscript file or printer.

Dec 01, 20 transparent polygon shapes from shapefiles. It is easiest to do this using transparency, but in my test using the postscript driver, the transparent color fills do not appear. More recently, the remaining 8 bits have been used to store an alpha channel to represent colour transparency. W ith idl, you can quickly access image data and begin investigating the best way to extract useful information. The color of the polygon is multiplied by the alpha value and the pixels already on the screen are multiplied by 1.

In later versions of idl, this can be an issue unless you specify the compile options inside routines. The tvrd function reads the contents of either buffer to an idl array. Theyre good enough to get real work done, so im offering them free under the gpl. The goal of an idl is to describe the interface for some service so that clients wanting to use the service will know what methods and properties, the interface, the service provides. Object programming michigan technological university. All of the idl plotting and graphics routines work with the zbuffer device driver. This code implements the polygon as a control structure which takes a radius and a repeat count number of polygon points and calls the userdefined procedure at each point by scaling and rotating the ctm. In addition, the polyfill procedure has a few keyword parameters, allowing gouraud shading and warping images over 3d polygons, that are only effective when used with the zbuffer. Currently, the polygon is drawn on top of the existing plot, but the color is not transparent so i cannot see the data that is below the polygon. Polyfill uses the current graphics devices own polygon filling.

To add a driver to ghostscript, first pick a name for your device. Feature windows os x linux solaris intel 32bit intel 64. Postscript positioning using the xoffset and yoffset keywords often, idl users are confused by the use of the xoffset and yoffset keywords to the postscript device routine. Similarly, when output to an eps file, this image will only fill a small portion of the.

Printing polygons with transparency autodesk community. This field only has meaning for devices that write to a file if the file is accessible to the user from idl, and is 0 if no file is open. Postscript 3 and newer includes many enhancements to older versions of postscript, including improved image quality and color. For more information on this routine, refer to the idl online help navigator or.

I opened the file with cgshapeinfo and it looks to me like the values in the shapefile are not even in latitude and longitude. Polygon group polygon buffer cleared polygon mode off. Weve all seen it before, illegible labels on a figure in a paper or talk. By default, polyfill fills the polygon with a solid color. Set this keyword to select the helvetica postscript font. Keywords accepted by the idl devices harris geospatial solutions. Feature support by operating system installation and licensing guide feature support by operating system the following table shows marks indicating which platforms support the corresponding feature. If you execute any of these as an asynchronous command in an mp session, they are given default answers of null characters or strings, or the end command in the case of the. Idl will warp the image from degrees to meters and overlaid onto the map projection. The interface between ghostscript and device drivers.

Ive addressed the topic of postscript output on my idl figures page but in this post im just going to. To start viewing messages, select the forum that you want to visit from the selection below. Idl therefore assumes that the plotter cannot, and generates all polygon operations in software using line drawing. The logical number of the file open for output by the current graphics device. Both will use loops, and the second will require learning about arrays. All arguments except file default to values given by ps. The default settings are given in default postscript driver settings.

How to colour polygons with a completely transparent fill. Idl controlc stops the excecution of a program maybe you have put a stop in your program and you want to print out the current value of a variable idl print, array0. Its purpose is to demonstrate the best programming practices for creating direct graphics graphical output in idl. Use the returned reference to manipulate the annotation after creation by changing properties or by calling methods. Idl provides many tools for displaying, modifying and analyzing images. Idl tutorial for astronomy 361 optical university of michigan. This usually occurs when using hatch patterns from the default fill palette. The polyfill procedure fills the interior of a region of the display enclosed by an arbitrary two or threedimensional polygon.

Please note that i create postscript files almost exclusively as intermediate files in the production of high. For the printing system getting access to the printerspecific features the manufacturer supplies a ppd file for every postscript printer. So far, weve been using the graphics window on the screen, but there are several other graphics devices accessible in idl see table 5. However, if you want to add labels to the cutout spaces, then you will need to add using a union tool the smaller polygons back to the mask. I wish to display only a single county, summit county, on a map. Not all methods are available on every hardware output device. Please note that i create postscript files almost exclusively as intermediate files in the production of high quality png, jpeg, tiff and pdf fil.

Idl is actually drawing a set of polygons calculated from the font information. Atv is a program for display and analysis of astronomical images using the idl imageprocessing language. Specifying a nonzero value for the polyfill keyword causes idl to use the hardware polygon. All arguments except file default to values given by pdf. Creating transparent image overlays it is possible to create and display a transparent image using either idl direct graphics or idl object graphics. Although primarily used for 3d graphics, the zbuffer driver can be used to create 2d objects in a frame buffer in memory. Idl programmer assumed that the red on black color scheme in idl graphics windows was just the strange way idls designers had planned it. For example, the postscript driver fills this field with the unit number of the file open for postscript output. Alpha transparency in r graphics paul murrell august 17, 2004 internally, r stores colours as 32bit integers. What you really should be doing here is setting the background color value to the index of the white.

I cannot draw the polygon first and then redraw the plot using oplot because i do have have access to the. Set this property to an idl variable of any data type. When the background colour is fully transparent as is the initial default value, the postscript produced does not paint the background. Postscript clipboard output can be generated using the cmyk color model. That old manuscript preparation document that said figures should fill a lettersized page is misguided. The idl polyfill procedure fills the interior of arbitrary polygons given a list of vertices. So its a loop, that makes the user point 1,0 map to successive points of the polygon. It allows interactive control of the image scaling, color table, color stretch, and zoom, with support for world coordinate systems. The interface definition language idl is not a programming language, but a descriptive language to describe the interfaces being implemented by objects. Free graphics software for the tex, latex, and pstricks community. I realize cgimage has a transparent keyword that can be used to set the transparency of an image when it is displayed, but i really dont understand the purpose or role of the various transparency keywords that are available in cgimage, or even how such transparency can be used.

The idl zbuffer device is a pseudo device that draws 2d or 3d graphics in a buffer. Hp pclpjl referenceset pcl 5 printer language technical quick reference guide printed on recycled paper. Is there any way i can get a background color other than white answer. Restricted rights notice the idl, idl advanced math and stats, envi, and envi zoom software programs and the accompanying procedures, functions, and documentation described herein are sold under license agreement. Note that if you connect with the x server by creating a window or using the device keyword to the help procedure, the visual class will be set. Provides a deviceindependent and colormodelindependent way to fill a polygon with a particular color. Idl addssubtract arrays as easy as if scalars, if arrays are compatible idl legend,residual image the exercise and postscript plot of this section will be to draw 1d scans through this image, one along the peak in x and one along the peak in y curves should be labeled in the legend. Create a second image the same size as your first, with a black background. Creating transparent image overlays dartmouth college. Pixels less than the value of transparent are not drawn, simulating.

Specifying a nonzero value for the polyfill keyword causes idl to use the hardware polygon filling. Within idl, you define the name of the interface, the names of each of the attributes and methods, and so forth. There are times i want to change the fill color of each poly from whatever it is to transparent. It therefore includes postscript commands to position the plot on the page and to eject the page from the printer. Normally when you type an idl traditional graphics command, the window is first erased with the background color. It returns a third image, which should have a semi transparent polygon on it. Almost all postscript viewers will use a white canvas so the visual effect is if the background were white. The topics in this section are meant to get you started with a basic set of tools. Idl is an acronym for interface definition language of which there are several variations depending on the vendor or standard group that defined the language. Aper counts subpixels, but uses a polygon approximation for the intersection of a. Visit the coyote plot gallery for examples of well over 50 different types of colorful graphics plots that can be sent directly to postscript files. Postscript is a turingcomplete page description programming language, designed and developed by adobe. Im not quite sure what pixel data youre referring to, so ill assume its another array which you can index with the shapefile coordinates.

The idl postscript device driver accepts many of the standard embedded formatting commands, and is described here. Free graphics software for the tex, latex, context. From the start, 24 bits have been used to store three 8bit channels for red, green, and blue. Postscript level 2 1991 contained several important improvements. Using these data, we are now ready to do some plotting.

Creating a transparent image is useful in the warping process when you want to overlay a transparency of the warped image onto the reference image the image in which xo, yo control points were. This program is designed to create nicely formatted contour levels for use in contour plots. I cannot draw the polygon first and then redraw the plot using oplot because i do have have access to the idl source code. This will not be the case when printing onto coloured paper, though. The way to specify simple modules with idl is so straightforward that we choose to give only examples at first. Pixels less than the value of the transparent keyword are not drawn. This is a gallery of example idl programs and graphics plots, written using coyote graphics routines. Nov 06, 2000 on the linux side my plot20 window comes up with a white background, on the windows side a black one. Jan 10, 20 working with transparent images and cgimage. I can get any background color i like in my postscript file as long as as i really like white. The background of a polygon theme appears transparent on the screen, but becomes solid when printed. Alpha transparency in r graphics department of statistics.

These commands are undesirable if the output is going to be inserted into the middle of another postscript document. A vector of indices into the color table for the color of each vertex polygon data point. This array may then be further processed, written to a file, or output to a rasterbased graphics output device. The zbuffer device is a pseudo device in that drawing commands update buffers in memory rather than sending commands to a physical device or file. Well, that and that you should be using s instead of s to index arrays. The interior of the polygon can be filled with a solid color or with some devices, a userdefined fill pattern contained in a rectangular array.

In any idl file, there can be one or more interface definitions defined as part of a module. Keywords accepted by the idl devices dartmouth college. The colormapvisual class combination is chosen when idl first connects with the x window server. This causes idl to use the postscript driver for producing graphical output. For example code look at our github repo, feel free to put in a pull request to add more examples. The plot command we can call plot with several keywords and optional inputs, and these are what well explore here. Making fonts better in idl postscript output astrobetter. I have a linear plot that i would like to draw a polygon on top of, but still be able to see the underlying plot. The differences between the postscript and pcl drivers. You can find more information on the websockets documentation page. The printer and its driver do not support postscript.

The idl zbuffer device is a pseudo device that draws 2d or 3d graphics in a buffer contained in memory. This book explains how to process images using idl interactive data language. Destination objects a window, printer, clipboard or memory buffer that. There are several kinds of loop constructs in postscript. Fonts 2473 idl reference guide fonts in idl direct vs. The device command allows you to do various things to control which postscript file your output goes to, how big your plot will appear, and so on. The polygon function returns a reference to the created annotation.

Then, with an sld file in mapserver, you can style the mask as transparent gray, and style the cutouts as completely transparent, and apply the labels there. I guess that was shooting a little too fast, but the ensuing discussion i. If this is your first visit, be sure to check out the faq by clicking the link above. Idl technologies not listed in this table are assumed to work on all supported platforms. The file argument is interpreted as a c integer format as used by sprintf, with integer argument the page number the default gives files rplot001. I have a map that will contain a group of colored polygons. A modified idl container with properties needed for coyote graphics routines. The ultimate defaults are quoted in the arguments section. I dont know how to remedy this problem in supermongo or other popular plotting programs, but i do in idl. The illustration of a pdffile, in that transparent polygons were received, is really slow or the transparence of color is lost on paper or in a pdfdocument. Idl is a highlevel programming language that contains an extensive library of image processing and analysis routines. Command line idl for windows, for idl 7 resources for idl. This driver implements the classic z buffer algorithm for hidden surface removal. Although there may be workarounds liam, it still would be much preferrable to see 24bit postscript colors produced by the postscript driver.