
FilterFormula Revision history
==============================

1.0beta: 
========
16.09.1998  1st Release

17.09.1998  Fix for Registry initialization (Filter would not start)

18.09.1998  Fix in exclusive-or sign '^' (resulted in a syntax error)
            Exchange of the '+' and '-' buttons

19.09.1998  fixed: Division by zero in xsrc(x,y,d,z) when d=0
            rst() function implemented
            implemented: cmax, rmax, gmax, bmax, amax, imax, umax, vmax, 
                         dmin, mmin, zmin, cmin, rmin, gmin, bmin, amin, imin, umin, vmin, tmin, pmin
                         (treated as constants)
            C, R, G, B, A, I, U, V:  only when the .afs file is imported (not in edit window)

20.09.1998  fixed: Crash in About... from Photoshop "Help" menu
            Max. code size set to 4 KB also in shareware version
            Display of scaling factor above preview window
            default display at maximum scaling ratio (so that subsampled whole image is shown)
            
21.09.1998  improved full display of preview window
            corrected: crash of Paint Shop Pro 5 during zooming and panning
            there is still an error in Corel PPaint 7: cannot subsample image

22.09.1998  bigger preview window
            new features: 
            - up to 6 user-selectable colors (Press the coloured buttons to select)
            - possibility to select a center point in the preview image
              (by pressing right button, marked by a black cross in preview)
            file storage altered: all filters must be recompiled!

24.09.1998  fixed: '|' (binary OR) operator 
            fixed: color selectors 5 and 6 were not accessible
            new option: 2 checkboxes (accessed via chk(nr) function)
            different default slider settings for each slider (saved when OK pressed)            
            fixed: even if selection is used, the whole image is used as image source
                  (not only the selection)                        
            Checkbox "Filtering" allows to control whether the filtered or the
                  original image is shown in preview window
            fix in .afs import feature (in some cases e.g.ctl() was translated 
                  to rtl() or similar)
            
27.09.1998  more accurate sin() and cos() functions
            fixed: error in trackbar handling (couldn't be dragged to values
                   below zero)
            fixed: Error in Corel PhotoPaint 8 compatibility
            zooming is done so that the center of preview stays the same
            
29.09.1998  changed the calculation of mathematical and trigonometric functions 
                to calculation with numeric Coprocessor 
                (sin, cos, sqr, c2d, c2m, r2x, r2y, variables d & m)
            some minor speed improvements
            cosmetic and internal changes
            
30.09.1998  color picker selects color from preview image:
               press any color selector field while holding down the "Shift" key. Move the 
               picker cursor to the desired position on the preview image (you can pan it and
               change the magnification factor) and press the left mouse button plus shift key. 
            allocation size increased ("Memory heap overflow")

01.10.1998  changed shape of color picker
            fixed: preview filtering is stopped if it takes longer than 2 seconds
               (and a white X is drawn over the image)        
            new function pow(x,p1,p2)  returns x**(p1/p2)
               this enables you also to calculate root functions of a value (not only square)

05.10.1998  fixed: error in registry initialization (could lead to crash)
            first samples of standalone filters created
            
14.10.1998  small dialog redesign
            SHIFT '+', SHIFT '-'  switches to min/max. resolution
            Warning messages window below editing window in compiler dialog
            Warning messages are issued if values are assigned to system vars, or the variables "c" or "z" 
                are used (possible error causes)
            System variable "inpreview" is 1 in preview window and 0 during actual filtering process
            
01.11.1998  introduction of system variable "msk" which represents the mask value of the current pixel. 
            The fifth channel in the src() function (z=4) returns the mask value of a certain point.
            fixed error with preview window in Paint Shop Pro 5 (could lead to a crash)
            Installation program "Setup" ready
            Transformation of help system to HTML completed.
