Next: , Previous: , Up: Internal Routines   [Contents][Index]

15.5.837 zoom

zoom, data [, bitmap1, bitmap2]

[x11] a routine for inspecting sets of images.

data must contain an array with at least two dimensions. a two-dimensional slice through the data is displayed in the center of the current window (based on the current values of the associated global variables: see below) and a menu of options is shown. If bitmap1 or bitmap2 are specified, then the "three-colors" color table is loaded (threecolors) and corresponding slices through data, bitmap1, and bitmap2 are displayed as if with tv3. Currently, the options are:


Shows the current magnification factor. If you click the pointer in this entry, then you are queried for a new magnification factor.

Standard Zoom

Returns to the default situation: magnification factor 1, with the image center in the center of the window.

Zoom In (2) Out

Zooming in or out by a factor of 2. If you click to the left of the 2 (e.g., on "In"), then you zoom in. If you click to the right, then you zoom out.


If you click on this, then you can select a new position in the image to become the center of attention. If the image fills the whole window, then the selected position will be at the very center.


This selection enables moving of the displayed image part by moving the pointer away from the center of the window in the desired direction. The futher the pointer is from the center of the image, the further the image moves in each step. The image only moves while the pointer is moved, too. Clicking the pointer anywhere in the window, or re-selecting the "Move" entry in the menu aborts the moving.


By default, contrast is determined for each displayed image separately such that black corresponds to the lowest value and white to the highest value. By selecting "Fix", the values that black and white correspond to are the extreme values in the current image. By selecting "Let", the default behavior is restored. The used contrast limits are displayed on the next line: If both values are zero, then default behavior is active. After clicking on one of these numbers, you are queried for a replacement value for that number.


If one or two bitmaps are specified in the call to zoom, then this entry governs the color contrast of the bitmaps. If you enter a new value, then this value produces a new color table as if it was specified in a call to threecolors.


Steps through the images. If you click on the less-than sign (<), then you move one frame back. If you click on the double less-than sign (<<), then you move back by 5 frames. Likewise, greater-than signs move you forward. The end of the frame range is taken to connect to the beginning.


Play the images in a movie. Every time you click to the right of the x, the play speed gains one unit of forward speed. Every time you click to the left, the play speed gains one unit of backward speed. The speed is indicated (up to 3 units) by the number of less-than or greater-than signs shown (which is one more than the speed, up to 4 signs). If you click on the x, then the movie is stopped.


Shows the data dimensions that correspond to the x and y axis, respectively. By clicking on the dimensions you can advance them cyclically to any desired value. If the two dimensions are unequal, then the corresponding new image is shown. If the dimensions are equal, then they do not indicate an image, and then nothing new is shown except that the colon (:) after "Dims" is replaced by an asterisk (*).

Mouse Position

By default, the coordinates and data value shown are those associated with the current pointer position in the image. If you click on this option, then you can select a fixed position in the image. The coordinates and data value at that fixed position are then shown and the option changes to "Fixed Position". If you click on this again, then the default behavior results again.

x, y

Shows the current image data coordinates corresponding to the pointer position. If the pointer is outside the image, then the nearest (in some sense) position inside the image is used instead.


Shows the number of the currently displayed frame. All dimensions other than those currently displayed are lumped together to yield a frame number.


Shows the image value corresponding to the current pointer position.


Quits zoom

The following global variables are set by this routine: !zoomx (the x coordinate – measured in data units – of the center of the displayed image part), !zoomy (the y coordinate of the center), and !zoommag (the magnification factor). The values of these variables are used as defaults for the next call to zoom.

See also: threecolors, tv3, !zoomx, !zoomy, !zoommag

Next: , Previous: , Up: Internal Routines   [Contents][Index]