Adding dithering algorithms, examples, and documentation to IMGADJ lib.

- Implement Floyd-Steinberg dithering test with adjustable amount and reset functionality.
- Create comprehensive dithering test showcasing all 22 dithering algorithms with interactive controls.
- Introduce random and noise dithering test featuring random and blue noise algorithms with seed control.
- Develop ordered dithering test demonstrating various Bayer matrices and their effects on images.
- Add special pattern dithering test highlighting halftone, spiral, and clustered dot dithering techniques.

Author: grymmjack

IMGADJ/IMGADJ.BI

@@ -42,13 +42,43 @@ CONST GJ_IMGADJ_PIXELSCALER_HQ2XB     = 5
 CONST GJ_IMGADJ_PIXELSCALER_HQ3XA     = 6
 CONST GJ_IMGADJ_PIXELSCALER_HQ3XB     = 7
 
+' Dithering Algorithm Constants
+CONST GJ_IMGADJ_DITHER_ORDERED_2X2           = 0
+CONST GJ_IMGADJ_DITHER_ORDERED_4X4           = 1
+CONST GJ_IMGADJ_DITHER_ORDERED_8X8           = 2
+CONST GJ_IMGADJ_DITHER_ORDERED_16X16         = 3
+CONST GJ_IMGADJ_DITHER_FLOYD_STEINBERG       = 4
+CONST GJ_IMGADJ_DITHER_JARVIS_JUDICE_NINKE   = 5
+CONST GJ_IMGADJ_DITHER_STUCKI                = 6
+CONST GJ_IMGADJ_DITHER_BURKES                = 7
+CONST GJ_IMGADJ_DITHER_SIERRA                = 8
+CONST GJ_IMGADJ_DITHER_SIERRA_LITE           = 9
+CONST GJ_IMGADJ_DITHER_ATKINSON              = 10
+CONST GJ_IMGADJ_DITHER_FALSE_FLOYD_STEINBERG = 11
+CONST GJ_IMGADJ_DITHER_FAN                   = 12
+CONST GJ_IMGADJ_DITHER_STEVENSON_ARCE        = 13
+CONST GJ_IMGADJ_DITHER_TWO_ROW_SIERRA        = 14
+CONST GJ_IMGADJ_DITHER_SHIAU_FAN             = 15
+CONST GJ_IMGADJ_DITHER_RANDOM                = 16
+CONST GJ_IMGADJ_DITHER_BLUE_NOISE            = 17
+CONST GJ_IMGADJ_DITHER_CLUSTERED_DOT         = 18
+CONST GJ_IMGADJ_DITHER_HALFTONE              = 19
+CONST GJ_IMGADJ_DITHER_SPIRAL                = 20
+CONST GJ_IMGADJ_DITHER_INTERLEAVED_GRADIENT  = 21
+
 ''
 ' SHARED STATE FOR OPTIMIZATIONS
 '
 
 DIM SHARED GJ_IMGADJ_noise(0 TO 65535) AS INTEGER
 DIM SHARED GJ_IMGADJ_noiseInit AS INTEGER
 
+' Dithering cache for palette color lookups
+DIM SHARED GJ_IMGADJ_dither_cache_r(0 TO 255) AS INTEGER  
+DIM SHARED GJ_IMGADJ_dither_cache_g(0 TO 255) AS INTEGER
+DIM SHARED GJ_IMGADJ_dither_cache_b(0 TO 255) AS INTEGER
+DIM SHARED GJ_IMGADJ_dither_cache_valid AS INTEGER
+
 ' --- Function Declarations ---
 DECLARE SUB GJ_IMGADJ_Init
 DECLARE SUB GJ_IMGADJ_RGBtoHSV (r AS INTEGER, g AS INTEGER, b AS INTEGER, hue AS SINGLE, sat AS SINGLE, value AS SINGLE)
@@ -79,3 +109,27 @@ DECLARE FUNCTION GJ_IMGADJ_ColorBalance (sourceImg AS LONG, redShift AS INTEGER,
 DECLARE FUNCTION GJ_IMGADJ_Colorize (sourceImg AS LONG, hue AS INTEGER, saturation AS SINGLE) AS LONG
 DECLARE FUNCTION GJ_IMGADJ_Pixelate (sourceImg AS LONG, pixelSize AS INTEGER) AS LONG
 DECLARE FUNCTION GJ_IMGADJ_PixelScaler (sourceImg AS LONG, scalerType AS INTEGER) AS LONG
+
+' --- Dithering Functions ---
+DECLARE FUNCTION GJ_IMGADJ_DitherOrdered2x2 (sourceImg AS LONG, amount AS SINGLE) AS LONG
+DECLARE FUNCTION GJ_IMGADJ_DitherOrdered4x4 (sourceImg AS LONG, amount AS SINGLE) AS LONG  
+DECLARE FUNCTION GJ_IMGADJ_DitherOrdered8x8 (sourceImg AS LONG, amount AS SINGLE) AS LONG
+DECLARE FUNCTION GJ_IMGADJ_DitherOrdered16x16 (sourceImg AS LONG, amount AS SINGLE) AS LONG
+DECLARE FUNCTION GJ_IMGADJ_DitherFloydSteinberg (sourceImg AS LONG, amount AS SINGLE) AS LONG
+DECLARE FUNCTION GJ_IMGADJ_DitherJarvisJudiceNinke (sourceImg AS LONG, amount AS SINGLE) AS LONG
+DECLARE FUNCTION GJ_IMGADJ_DitherStucki (sourceImg AS LONG, amount AS SINGLE) AS LONG
+DECLARE FUNCTION GJ_IMGADJ_DitherBurkes (sourceImg AS LONG, amount AS SINGLE) AS LONG
+DECLARE FUNCTION GJ_IMGADJ_DitherSierra (sourceImg AS LONG, amount AS SINGLE) AS LONG
+DECLARE FUNCTION GJ_IMGADJ_DitherSierraLite (sourceImg AS LONG, amount AS SINGLE) AS LONG
+DECLARE FUNCTION GJ_IMGADJ_DitherAtkinson (sourceImg AS LONG, amount AS SINGLE) AS LONG
+DECLARE FUNCTION GJ_IMGADJ_DitherFalseFloydSteinberg (sourceImg AS LONG, amount AS SINGLE) AS LONG
+DECLARE FUNCTION GJ_IMGADJ_DitherFan (sourceImg AS LONG, amount AS SINGLE) AS LONG
+DECLARE FUNCTION GJ_IMGADJ_DitherStevensonArce (sourceImg AS LONG, amount AS SINGLE) AS LONG
+DECLARE FUNCTION GJ_IMGADJ_DitherTwoRowSierra (sourceImg AS LONG, amount AS SINGLE) AS LONG
+DECLARE FUNCTION GJ_IMGADJ_DitherShiauFan (sourceImg AS LONG, amount AS SINGLE) AS LONG
+DECLARE FUNCTION GJ_IMGADJ_DitherRandom (sourceImg AS LONG, amount AS SINGLE) AS LONG
+DECLARE FUNCTION GJ_IMGADJ_DitherBlueNoise (sourceImg AS LONG, amount AS SINGLE) AS LONG
+DECLARE FUNCTION GJ_IMGADJ_DitherClusteredDot (sourceImg AS LONG, amount AS SINGLE) AS LONG
+DECLARE FUNCTION GJ_IMGADJ_DitherHalftone (sourceImg AS LONG, amount AS SINGLE) AS LONG
+DECLARE FUNCTION GJ_IMGADJ_DitherSpiral (sourceImg AS LONG, amount AS SINGLE) AS LONG
+DECLARE FUNCTION GJ_IMGADJ_DitherInterleavedGradientNoise (sourceImg AS LONG, amount AS SINGLE) AS LONG