/etc/X11
Edit the file XF86Config-4 (or XF86Config if you are running RedHat 8).
Under Section "Device" add the line:
Option "backingstore"
The user may specify the positions of all the 'positionable' IDP3 widgets in the idp3_preferences file. These X,Y pairs of integers specify the position of the top-left corner of the indicated widget with respect to the top-left corner of the display screen. These preferences are useful when running IDP3 on very small computer screens. When most of the IDP3 widgets are closed (clicking on the button) the current position of the widget on the screen is recorded. If the user has moved the widget on the screen it should return to the moved position when reopened.
The user can specify the colors used for drawing the radial profile circle, the cross section line, and the noise profile annuli in the roi window. Six colors are available: 0=Black, 1=White, 2=Red, 3=Green, 4=Blue, 5=Yellow. Using these colors limits the image display colors to 250 levels instead of 256 because the lowest six levels are allocated to the six colors described above. When the user adjusts his image display with the gamma correction in the Load Color Table Widget (which can be accessed through the Adjust Display Widget) he may get unpredictable results because these six reserved colors may be moved into the range of the image display. To turn off the color displays the user may set color_radpf, color_poly, color_innernpf, color_outernpf, color_xsect, color_spsh, color_orient, and color_roi to -1 or by clicking the reset button in the set colors widget [main file menu]. These items will then be displayed in color level 200. In a black and white linear scale the color will be white.
Large images use lots of memory. Many images use lots of memory.
When lots of memory is in use, the program may slow down.
If you click "Done" to close a window, the memory will also be cleared. If you use the corner "x", the memory for that window will still be allocated.
IDP3 uses bi-cubic interpolation for sub-pixel shifts. Previously bi-linear interpolation was used but bi-cubic appears to do better. For zooming images, the user has the choice of bi-linear, bi-cubic sinc or bi-cubic spline interpolation or pixel-replication. Any one of these four interpolation methods can be used in either of two places: zooming images in the main display window and zooming subsections of the main display window in the ROI display window. Different interpolation methods have advantages in different situations. The results of zooming data varies slightly according to the Pixel Origin definition in the preferences file. The default pixel origin of IDL, i.e., for the first pixel where [0,0] falls on that pixel, is the pixel center. This assumes the lower left corner of the first pixel is [-0.5,-0.5] and the upper right corner is [0.5,0.5]. Some users prefer to consider the range of the pixel to be [0,0] to [1,1] and the pixel origin to be the lower left corner. If the alternate definition is chosen idp3 will shift the data in the roi by 1/2 original pixel when zoomed by interpolation. The cursor readback and centroid results will then have the lower left corner of the pixel as its origin.
When an image is zoomed, in this case, zoomed in the ROI window, one may conserve total flux in an object or one may conserve the flux per area. To conserve total flux when zooming, the value of the zoomed pixels must be divided by the square of the zoom factor. To make these rescaled pixels display properly in the ROI window, the Z1 and Z2 lower and upper greyscale boundaries must also be divided. To conserve flux or not to conserve flux is an option the user may specify in his or her preferences file or edit on-the-fly.
Both FITS,PICT, and HDF are acceptable input formats for images and masks. All output images are formatted as FITS files. If the input file is a multiple image extension FITS, the output will be a FITS file with a single image extension. If the input is in HDF format, a simple FITS file with minimal header is the output, unless a FITS type header is contained in the input HDF file.
Many calculations and functions are performed on data within idp3 at the subpixel level. It is therefore important to establish the definition of the pixel origin. Idp3 has two options:the conventional definition at the center of the pixel, (.5,.5) for the first pixel, and the alternate definition at the lower left corner, (0,0) for the first pixel. The user selects which definition to use by setting the parameter, pixel_origin, in the idp3_prefernces file. When the alternate definition is chosen, the zoomed image in the ROI is shifted by 0.5 original pixels when interpolation is used in order to place the pixel origin at (0,0). Some idp3 functions, e.g. image rotation, expect the center of rotation to be specified with the conventional definition of the pixel origin. When the alternate definition is specified, 1/2 pixel is subtracted from the rotation center coordinates before the data is rotated.
Each time the user makes a change in the Adjust Position or Show Images Window, the image in the Main Display Window is recalculated from the original data of the "on" images. Regardless of the order in which the user selects various operations, these operations are always performed in the following order:
If the settings on your computer are not set right, then some images in idp3 will be "erased" when another window is passed in front of it. This can be corrected.
As the root user, go to the directory
/etc/X11
Edit the file XF86Config-4 (or XF86Config if you are running RedHat 8).
Under Section "Device" add the line:
Option "backingstore"
I ran into the problem on my laptop while running idl_5.5 where the colors where acting oddly.
Turns out that a file wasn't transfered correctly. So if you've tried all of the "standard" fixes like
IDL> device, true_color=24,retain=2, decomposed=0
but nothing works, try replacing the following file in:
/usr/local/rsi/idl_5.5/bin/bin.linux.x86
mv libidl.so.5.5 libidl.so.5.5.old
And replace it with libidl.so.5.5. You will have to be root to do this.