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(Although this button is not normally active (see below), this is a convenient place for information about zooming, and other related issues.)

Introduction top

Images are associated with image windows. The name of the window (which is also the name of the file from which the image was read, but which can be changed) is the name of the image, and is used to name the file if the image is stored. The image window, along with the original image data, also has a scaled image, a pixmap and a look up table which are used for display. Pixel operations use the original image data, which usually remains unaffected. Scaling affects the scaled image, and in turn, the pixmap, but not the original data. The color sliders and various graphics affect only the pixmap. The scaled image and pixmap are never stored to a file - only the image data. Graphics are saved using screen grabs (such as command-shift-3 or Capture).

If memory is a consideration due to the size or number of images loaded at any one time (all image data is kept in memory as with NIH Image, NOT in virtual memory on the disk as with Adobe Photoshop) then the auto_show parameter shoule be turned OFF.

In this case, MacLispix is unlike most image processing programs, in that image files will not be displayed when you load them, but are shown as a window title bar without the rest of the window. The image array is associated with this window - the name is shown in the title bar. Actually displaying the images takes more memory than just loading them. Closing the window (whether displayed, or only a title bar) will effectively erase the image array and make the memory available.

To display windows shown only as a title bar, use the show button.

Except for byte images, arrays are scaled linearly and displayed in a gray level window. Byte images with close to the full range (0 - 255) of pixel values are not scaled because this results in a much faster display. Byte images have an array element type of '(unsigned-byte 8), that is, the elements are bytes consisting of 8 bits each. This does not mean that byte images will always look good when displayed without scaling -- if the range of values is small, the image will be scaled. Images with values in the range 0-255, but which do NOT have array-element-type '(unsigned-byte 8), are not considered byte images (at least at the moment, and will be scaled automatically.

Grow square top


 The grow square is the small region at the lower right of an image, which may be dragged to grow or shrink an image. This is the mouse equivalent of the zoom button.

The icon at the right of the title bar is the

zoom box. (see zoom)


When growing images, the aspect ratio is preserved, and any zoom size is allowed. This behavior is modified by the control and option keys:

Resizing options with the grow square are controlled by these keys:

Grid snap parameter | top

Have caps lock key down. Mouse window on the image itself with control key down. Mousing the title bar will move the window smoothy as usual.

Change size of grid with the grid_spacing parameter.

Note - the control key has two uses. When growing the window, it allows making the window any size with respect to the original array, keeping the same aspect ratio. When mousing anywhere in the window, it has the mouse 'grab' the window in order to move the window. This makes the entire window act the same as the title bar, as far as moving the window goes (except for the grid snap option, which works only with the option key down and not on the title bar). This is useful when the title bar is not visible (such as when the image is larger than the screen and you are looking at the bottom) or when the window has no title bar. Images with special borders (or no border) have no title bar, and labels, axes, etc. also have no title bar.

(top) | (Overlay)

Showing Images - Example

This is an example of displaying images, that have been loaded from the hard disk.

Here are the images after loading with
MLx->Image Files->TIFF->Load Multiple, and then using the
Arrange -> Cascade All button.
This image is on its side due to the way in which LISP reads arrays, which happens to be collumn by collumn, rather than row by row, as with some other programming languages. This means that the image array, when brought from other computers, may be transposed - having the effect of flipping the image about a line from the upper left corner to the lower right corner. The solution is to transpose the array back again (with the Pixel Ops - Transpose button. Note that this button makes the images back into a title bar again, or leaves them that way if they were not displayed in the first place.
After transposition, the images look like this. Using the Arrange -> Cascade All button will reverse the ordering or layering of the windows, putting Kowala red in front.

Zoom buttontop(changing sizes of images)

The zoom button appears both in the images collumn and in the top image collumn. This button allows you to change the display sizes of your images. This (images collumn) can be useful when you want to increase the size of all of your images by the same amount. Simply select the zoom factor in the pop up menu.

Grow box top

The grow box located in the lower right hand corner of an image can be used to resize it. Holding down various keys while moving the grow box has these effects:

Zoom box top

Images can be brought back to the origional size by clicking on the zoom box.

moving large images

Zooming can make your images much larger than your actual screen. If you choose to do this, you can move around in your image by holding down the option key and the mouse button and moving the cursor around the screen.

If a very large image is just in the way, you can get rid of it by just clicking on it then typing command-w. Or, get the MLx buttons window in front using the MLx menu, then close the offending window with the arrange button.


Window titles (image names) top

The name of an image will be displayed in a title bar which lies across the top of the image. However, if the image is too small the entire name may not be shown completely. Instead, as much of the title as will fit into the title bar will be displayed. Use the Annotate -> Titles->Notes button in the Images collumn to display the window titles in smaller print.

Similar to other Macintosh applications, a dimmed title bar indicates that another window (or image window) is currently in use, in other words, another window is the front window. To get to the image window you desire simply click on that window or the title bar and the title bar will darken indicating that that window is now active. The image can also be selected in the Windows menu or the option-W menu.

To change the image title (the image name), use the Annotate -> Change Title button in the Top Image collumn , allowing you to simply replace the existing title with one more to your liking.