Exactly what appears under the ~SB~PixMap~SB~ menu depends upon the pix map PROCs installed in Vision Lab. If you are a programmer the ╥shared.h,╙ ╥Invert Clut,╙ and ╥Invert Clut.c╙ files will provide an example for adding your own pix map PROCs to Vision Lab. (Note the ╥Invert Clut╙ file is a LightspeedC project file)
Some PROCs may need special hardware or software to run. For example, a PROC that uses a hierarchical menu will be dimmed (unavailable) unless you are using system 4.1 or greater. The following are descriptions of the pix map PROCs that come with Vision Lab.
~F0~~s12~Apply Gray Map~F3~~s9~
Turns the pix map into a black and white image applying the brightness and contrast settings of the gray map. ~SB~16 Gray Levels~SB~ maps each pixel into values of 0 (for white) to 15 (for black). ~SB~256 Gray Levels~SB~ maps each pixel into values of 0 (for white) to 255 (for black).
~F0~~s12~Crop~F3~~s9~
Crop simply reduces the image to the portion of the image selected.
~F0~~s12~Expand~F3~~s9~
Converts a pix map of a lesser depth to a greater depth. ~SB~To 2 Bits~SB~, ~SB~To 4 Bits~SB~, and ~SB~To 8 Bits~SB~ choose the depth of the resulting pix map.
~F0~~s12~Filter~F3~~s9~
The functions available in Filter assume that 4 bit deep pix maps contain values from 0 (for white) to 15 (for black) and 8 bit deep pix maps contain values from 0 (for white) to 255 (for black). Using Apply Gray Map will force a pix map into these constraints. Although these functions are not intended to work on color images they can be used for creating some interesting ╥special effects.╙
~SB~Edge~SB~ is similar to the bit map PROC called contour. Edge, however, produces contours with various gray levels. ~SB~Smooth~SB~ produces a soft dulling effect on the selected portion of the pix map. ~SB~Sharpen~SB~ highlights features of the selected portion of the image.
~SB~The Most~SB~, ~SB~A Lot~SB~, and ~SB~A Little~SB~ control the strength of the filter on the image.
~SB~Box~SB~, ~SB~Plus~SB~, and ~SB~Cross~SB~ control the neighboring pixels that are used in the filtering process. Depending on the image you may notice ~SU~very~SU~ little difference between these options.
~F4~~C~
X X X O X O X O X
Box - X P X Plus - X P X Cross - O P O
X X X O X O X O X
~F3~~L~
~SB~Punctured~SB~ controls whether the center pixel ╘P╒ is used in the calculations. This option is only valid for smoothing.
~SB~Average~SB~ and ~SB~Median~SB~ control the type of smoothing performed. If you are experimenting with color images you may find Median smoothing much more desirable.
~F0~~s12~Flip~F3~~s9~
Flips the ~SU~selected~SU~ portion of the pix map either ~SB~Horizontal~SB~ or ~SB~Vertical~SB~.
~F0~~s12~Histogram~F3~~s9~
Produces a normalized histogram of the selected portion of the pix map. The gray map is applied to the pixel values when computing the histogram.
~F0~~s12~Invert Clut~F3~~s9~
Invert Clut simple does what it says. It inverts the entries in the color lookup table for the pix map. It does not change the values contained in the pix map in any way.
~F0~~s12~Rotate~F3~~s9~
~SB~Left~SB~ - Rotates the entire pix map image 90í to the left.
~SB~Right~SB~ - Rotates the entire pix map image 90í to the right.
Rotate will not work with a bit map window open.
~F0~~s12~Scale~F3~~s9~
Scale changes the pix map╒s size by applying the scaling factors set by ~SB~Set Scale~SB~. Unlike the Vision Lab functions Zoom In and Zoom Out, Scale actually changes the pix map in memory. You can scale the horizontal and vertical dimensions independently from /2 (0.500) to 2x (2.000). Color QuickDraw is needed for scaling pix maps with depths greater than one.
~F0~~s12~Squeeze~F3~~s9~
Squeeze does a number of things to the pix map to ~SU~try~SU~ to make it smaller in size. If there are any entries in the clut that map to the same color they are squeezed into the same value. Gaps in the numerical order of used entries are squeezed out. Also, the color table itself is sorted by red, green, and finally blue. If possible this command will also make the first entry in the color table white and the last entry black regardless of whether or not they are actually used in the image.
If there is a box around the pix map information in the information window using Squeeze PixMap will usually remove it. This is ~SU~very~SU~ important if you intend on saving the pix map as a PixelPaint or MacPaint file. It may also be important in other cases too.
