Fix LUT based optimization on 8 bits

Most times, optimization was discarded where it could be used. Monotonicity is not needed here. Added a small demo.

2 files changed, 152 insertions, 5 deletions

diff --git a/plugins/fast_float/src/fast_8_tethra.c b/plugins/fast_float/src/fast_8_tethra.c
index 7f72184..84c36a0 100644
--- a/plugins/fast_float/src/fast_8_tethra.c
+++ b/plugins/fast_float/src/fast_8_tethra.c
@@ -414,11 +414,7 @@ cmsBool Optimize8BitRGBTransform(_cmsTransform2Fn* TransformFn,
     // Check for validity
     lIsSuitable = TRUE;
     for (t=0; (lIsSuitable && (t < 3)); t++) {
-
-        // Exclude if non-monotonic
-        if (!cmsIsToneCurveMonotonic(Trans[t]))
-            lIsSuitable = FALSE;         
-
+        
         if (IsDegenerated(Trans[t]))
             lIsSuitable = FALSE;
     }
diff --git a/plugins/fast_float/testbed/demo_cmyk.c b/plugins/fast_float/testbed/demo_cmyk.c
new file mode 100644
index 0000000..d41f3f5
--- /dev/null
+++ b/plugins/fast_float/testbed/demo_cmyk.c
@@ -0,0 +1,151 @@
+//---------------------------------------------------------------------------------
+//
+//  Little Color Management System, fast floating point extensions
+//  Copyright (c) 1998-2022 Marti Maria Saguer, all rights reserved
+//
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+// 
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+// 
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+//---------------------------------------------------------------------------------
+
+#include "lcms2_fast_float.h"
+
+#include <stdlib.h>
+#include <memory.h>
+
+static
+void Fail(const char* frm, ...)
+{
+    va_list args;
+
+    va_start(args, frm);
+    vprintf(frm, args);
+    va_end(args);
+    exit(1);
+}
+
+
+
+#define ALIGNED_SIZE(a,x)  (((x)+((a) - 1)) & ~((a) - 1))
+
+
+static
+void* make_image(size_t size_x, size_t size_y, cmsBool fill_rgb, cmsUInt32Number* stride_x)
+{
+    cmsUInt32Number size_x_aligned = ALIGNED_SIZE(16, size_x);
+    cmsUInt32Number line_size_in_bytes = size_x_aligned * sizeof(cmsUInt32Number); // RGBA
+
+    cmsUInt8Number* ptr_image = (cmsUInt8Number*) calloc(size_y, line_size_in_bytes);
+    
+    if (ptr_image == NULL) Fail("Couldn't allocate memory for image");
+
+    if (fill_rgb)
+    {
+        size_t line;
+
+        for (line = 0; line < size_y; line++)
+        {
+            cmsUInt32Number* ptr_line = (cmsUInt32Number*)(ptr_image + line_size_in_bytes * line);          
+            cmsUInt32Number argb = 0;
+            int col;
+
+            for (col = 0; col < size_x; col++)
+                *ptr_line++ = argb++;
+                
+        }
+    }
+
+    *stride_x = line_size_in_bytes;
+    return (void*) ptr_image;
+}
+
+#define SIZE_X 10000
+#define SIZE_Y 10000
+
+static
+cmsFloat64Number MPixSec(cmsFloat64Number diff)
+{
+    cmsFloat64Number seconds = (cmsFloat64Number)diff / (cmsFloat64Number)CLOCKS_PER_SEC;
+    return (SIZE_X * SIZE_Y) / (1024.0 * 1024.0 * seconds);
+}
+
+
+
+static
+cmsFloat64Number speed_test(void)
+{
+    clock_t atime;
+    cmsFloat64Number diff;
+    cmsHPROFILE hProfileIn;
+    cmsHPROFILE hProfileOut;   
+    cmsHTRANSFORM xform;
+    void* image_in;
+    void* image_out;
+    cmsUInt32Number stride_rgb_x, stride_cmyk_x;
+
+
+    hProfileIn = cmsOpenProfileFromFile("sRGB Color Space Profile.icm", "r");
+    hProfileOut = cmsOpenProfileFromFile("USWebCoatedSWOP.icc", "r");
+
+    if (hProfileIn == NULL || hProfileOut == NULL)
+        Fail("Unable to open profiles");
+
+    xform = cmsCreateTransform(hProfileIn, TYPE_RGBA_8, hProfileOut, TYPE_CMYK_8, INTENT_PERCEPTUAL, 0);
+    cmsCloseProfile(hProfileIn);
+    cmsCloseProfile(hProfileOut);
+
+    
+    image_in = make_image(SIZE_X, SIZE_Y, TRUE, &stride_rgb_x);
+    image_out = make_image(SIZE_X, SIZE_Y, FALSE, &stride_cmyk_x);
+
+    atime = clock();
+
+    cmsDoTransformLineStride(xform, image_in, image_out, SIZE_X, SIZE_Y, stride_rgb_x, stride_cmyk_x, 0, 0);
+    
+    diff = clock() - atime;
+
+    free(image_in);
+    free(image_out);
+
+    cmsDeleteTransform(xform);
+    return MPixSec(diff);
+}
+
+
+int main(void)
+{
+    cmsFloat64Number without_plugin;
+    cmsFloat64Number with_plugin;
+    
+    fprintf(stdout, "DEMO of littleCMS fast float plugin: RGBA -> CMYK in Megapixels per second\n");  fflush(stdout);
+
+    // filling cache
+    fprintf(stdout, "Wait CPU cache to stabilize: ");  fflush(stdout);
+    speed_test();
+    fprintf(stdout, "Ok\n");
+
+    fprintf(stdout, "Without plugin: ");  fflush(stdout);
+    without_plugin = speed_test();
+    fprintf(stdout, "%.2f\n", without_plugin); fflush(stdout);
+
+    cmsPlugin(cmsFastFloatExtensions());
+
+    fprintf(stdout, "With plugin: ");  fflush(stdout);
+    with_plugin = speed_test();
+    fprintf(stdout, "%.2f\n", with_plugin); fflush(stdout);
+    
+    fprintf(stdout, "x %2.2f\n", (with_plugin/without_plugin)); fflush(stdout);
+
+    return 0;    
+}
\ No newline at end of file