deprecated RGB intensity functions and definitions. These coefficients do

2005-08-03  Sven Neumann  <sven@gimp.org>

	* libgimpcolor/gimprgb.[ch]: deprecated RGB intensity functions
	and definitions. These coefficients do not accurately compute
	luminance for contemporary monitors. Instead the coefficients from
	the sRGB spec should be used which have now been added.

	* libgimpcolor/gimpcolor.def: updated.

	* libgimp/gimpdrawable.c
	* libgimp/gimppixelfetcher.c
	* app/base/colorize.c
	* app/base/levels.c
	* app/base/temp-buf.c
	* app/core/gimpdrawable-blend.c
	* app/core/gimpdrawable-convert.c
	* app/core/gimpdrawable-desaturate.c
	* app/core/gimpimage-convert.c
	* app/core/gimpimage.c
	* app/gui/splash.c
	* app/widgets/gimpgradienteditor.c
	* modules/colorsel_triangle.c
	* plug-ins/common/aa.c
	* plug-ins/common/bumpmap.c
	* plug-ins/common/colorify.c
	* plug-ins/common/despeckle.c
	* plug-ins/common/displace.c
	* plug-ins/common/engrave.c
	* plug-ins/common/gradmap.c
	* plug-ins/common/grid.c
	* plug-ins/common/mng.c
	* plug-ins/common/newsprint.c
	* plug-ins/common/png.c
	* plug-ins/common/whirlpinch.c
	* plug-ins/gflare/gflare.c
	* plug-ins/gfli/gfli.c
	* plug-ins/maze/handy.c
	* plug-ins/pagecurl/pagecurl.c: use gimp_rgb_luminance() and
	friends instead of the deprecated intensity functions.

ChangeLog

+2005-08-03  Sven Neumann  <sven@gimp.org>
+
+	* libgimpcolor/gimprgb.[ch]: deprecated RGB intensity functions
+	and definitions. These coefficients do not accurately compute
+	luminance for contemporary monitors. Instead the coefficients from
+	the sRGB spec should be used which have now been added.
+
+	* libgimpcolor/gimpcolor.def: updated.
+
+	* libgimp/gimpdrawable.c
+	* libgimp/gimppixelfetcher.c
+	* app/base/colorize.c
+	* app/base/levels.c
+	* app/base/temp-buf.c
+	* app/core/gimpdrawable-blend.c
+	* app/core/gimpdrawable-convert.c
+	* app/core/gimpdrawable-desaturate.c
+	* app/core/gimpimage-convert.c
+	* app/core/gimpimage.c
+	* app/gui/splash.c
+	* app/widgets/gimpgradienteditor.c
+	* modules/colorsel_triangle.c
+	* plug-ins/common/aa.c
+	* plug-ins/common/bumpmap.c
+	* plug-ins/common/colorify.c
+	* plug-ins/common/despeckle.c
+	* plug-ins/common/displace.c
+	* plug-ins/common/engrave.c
+	* plug-ins/common/gradmap.c
+	* plug-ins/common/grid.c
+	* plug-ins/common/mng.c
+	* plug-ins/common/newsprint.c
+	* plug-ins/common/png.c
+	* plug-ins/common/whirlpinch.c
+	* plug-ins/gflare/gflare.c
+	* plug-ins/gfli/gfli.c
+	* plug-ins/maze/handy.c
+	* plug-ins/pagecurl/pagecurl.c: use gimp_rgb_luminance() and
+	friends instead of the deprecated intensity functions.
+
 2005-08-03  Michael Natterer  <mitch@gimp.org>
 
 	* libgimp/gimpprocbrowserdialog.[ch]: removed all parameters from

app/base/colorize.c

@@ -42,9 +42,9 @@ colorize_init (Colorize *colorize)
 
   for (i = 0; i < 256; i ++)
     {
-      colorize->lum_red_lookup[i]   = i * GIMP_RGB_INTENSITY_RED;
-      colorize->lum_green_lookup[i] = i * GIMP_RGB_INTENSITY_GREEN;
-      colorize->lum_blue_lookup[i]  = i * GIMP_RGB_INTENSITY_BLUE;
+      colorize->lum_red_lookup[i]   = i * GIMP_RGB_LUMINANCE_RED;
+      colorize->lum_green_lookup[i] = i * GIMP_RGB_LUMINANCE_GREEN;
+      colorize->lum_blue_lookup[i]  = i * GIMP_RGB_LUMINANCE_BLUE;
     }
 }
 

app/base/levels.c

@@ -194,7 +194,7 @@ levels_adjust_by_colors (Levels               *levels,
       guchar lightness;
 
       /* Calculate lightness value */
-      lightness = GIMP_RGB_INTENSITY (gray[0], gray[1], gray[2]);
+      lightness = GIMP_RGB_LUMINANCE (gray[0], gray[1], gray[2]);
 
       input = levels_input_from_color (channel, gray);
 

app/base/temp-buf.c

@@ -116,7 +116,7 @@ temp_buf_to_gray (TempBuf *src_buf,
       g_return_if_fail (src_buf->bytes == 3);
       while (num_pixels--)
         {
-          pix = GIMP_RGB_INTENSITY (src[0], src[1], src[2]) + 0.5;
+          pix = GIMP_RGB_LUMINANCE (src[0], src[1], src[2]) + 0.5;
           *dest++ = (guchar) pix;
 
           src += 3;
@@ -127,7 +127,7 @@ temp_buf_to_gray (TempBuf *src_buf,
       g_return_if_fail (src_buf->bytes == 4);
       while (num_pixels--)
         {
-          pix = GIMP_RGB_INTENSITY (src[0], src[1], src[2]) + 0.5;
+          pix = GIMP_RGB_LUMINANCE (src[0], src[1], src[2]) + 0.5;
           *dest++ = (guchar) pix;
 
           *dest++ = src[3];  /* alpha channel */

app/core/gimpdrawable-blend.c

@@ -820,7 +820,7 @@ gradient_put_pixel (gint      x,
   else
     {
       /* Convert to grayscale */
-      gdouble gray = gimp_rgb_intensity (color);
+      gdouble gray = gimp_rgb_luminance (color);
 
       if (ppd->dither_rand)
         {
@@ -1078,7 +1078,7 @@ gradient_fill_single_region_gray (RenderBlendData *rbd,
 
         gradient_render_pixel (x, y, &color, rbd);
 
-        *dest++ = gimp_rgb_intensity_uchar (&color);
+        *dest++ = gimp_rgb_luminance_uchar (&color);
         *dest++ = ROUND (color.a * 255.0);
       }
 }
@@ -1102,7 +1102,7 @@ gradient_fill_single_region_gray_dither (RenderBlendData *rbd,
 
         gradient_render_pixel (x, y, &color, rbd);
 
-        gray = gimp_rgb_intensity (&color);
+        gray = gimp_rgb_luminance (&color);
 
         *dest++ = gray    * 255.0 + (gdouble) (i & 0xff) / 256.0; i >>= 8;
         *dest++ = color.a * 255.0 + (gdouble) (i & 0xff) / 256.0;

app/core/gimpdrawable-convert.c

@@ -186,7 +186,7 @@ gimp_drawable_convert_grayscale (GimpDrawable      *drawable,
               d = dest;
               for (col = 0; col < srcPR.w; col++)
                 {
-                  val = GIMP_RGB_INTENSITY (s[RED_PIX],
+                  val = GIMP_RGB_LUMINANCE (s[RED_PIX],
                                             s[GREEN_PIX],
                                             s[BLUE_PIX]) + 0.5;
                   *d++ = (guchar) val;
@@ -217,7 +217,7 @@ gimp_drawable_convert_grayscale (GimpDrawable      *drawable,
               for (col = 0; col < srcPR.w; col++)
                 {
                   offset = *s++ * 3;
-                  val = GIMP_RGB_INTENSITY (cmap[offset+0],
+                  val = GIMP_RGB_LUMINANCE (cmap[offset+0],
                                             cmap[offset+1],
                                             cmap[offset+2]) + 0.5;
                   *d++ = (guchar) val;

app/core/gimpdrawable-desaturate.c

@@ -161,7 +161,7 @@ desaturate_region_luminosity (gpointer     data,
 
       for (j = 0; j < srcPR->w; j++)
         {
-          gint luminosity = GIMP_RGB_INTENSITY (s[RED_PIX],
+          gint luminosity = GIMP_RGB_LUMINANCE (s[RED_PIX],
                                                 s[GREEN_PIX],
                                                 s[BLUE_PIX]) + 0.5;
 

app/core/gimpimage-convert.c

@@ -760,8 +760,8 @@ color_quicksort (const void *c1,
   Color *color1 = (Color *)c1;
   Color *color2 = (Color *)c2;
 
-  double v1 = GIMP_RGB_INTENSITY (color1->red, color1->green, color1->blue);
-  double v2 = GIMP_RGB_INTENSITY (color2->red, color2->green, color2->blue);
+  double v1 = GIMP_RGB_LUMINANCE (color1->red, color1->green, color1->blue);
+  double v2 = GIMP_RGB_LUMINANCE (color2->red, color2->green, color2->blue);
 
   if (v1 < v2)
     return -1;

app/core/gimpimage.c

@@ -2064,7 +2064,7 @@ gimp_image_transform_color (const GimpImage    *dest_gimage,
         case GIMP_GRAY_IMAGE:
         case GIMP_GRAYA_IMAGE:
           /*  NTSC conversion  */
-          *dest = GIMP_RGB_INTENSITY (src[RED_PIX],
+          *dest = GIMP_RGB_LUMINANCE (src[RED_PIX],
                                       src[GREEN_PIX],
                                       src[BLUE_PIX]) + 0.5;
           break;

app/gui/splash.c

@@ -370,7 +370,7 @@ splash_average_bottom (GtkWidget *widget,
   gint          width, height;
   gint          rowstride;
   gint          channels;
-  gint          intensity;
+  gint          luminance;
   gint          count;
   guint         sum[3] = { 0, 0, 0 };
 
@@ -404,13 +404,13 @@ splash_average_bottom (GtkWidget *widget,
       pixels += rowstride;
     }
 
-  intensity = GIMP_RGB_INTENSITY (sum[0] / count,
+  luminance = GIMP_RGB_LUMINANCE (sum[0] / count,
                                   sum[1] / count,
                                   sum[2] / count);
 
-  intensity = CLAMP0255 (intensity > 127 ? intensity - 223 : intensity + 223);
+  luminance = CLAMP0255 (luminance > 127 ? luminance - 223 : luminance + 223);
 
-  color->red = color->green = color->blue = (intensity << 8 | intensity);
+  color->red = color->green = color->blue = (luminance << 8 | luminance);
 
   return gdk_colormap_alloc_color (gtk_widget_get_colormap (widget),
                                    color, FALSE, TRUE);

app/widgets/gimpgradienteditor.c

@@ -942,14 +942,12 @@ view_set_hint (GimpGradientEditor *editor,
   gimp_rgb_to_hsv (&rgb, &hsv);
 
   str1 = g_strdup_printf (_("Position: %0.6f"), xpos);
-
   str2 = g_strdup_printf (_("RGB (%0.3f, %0.3f, %0.3f)"),
                           rgb.r, rgb.g, rgb.b);
-
   str3 = g_strdup_printf (_("HSV (%0.3f, %0.3f, %0.3f)"),
                           hsv.h * 360.0, hsv.s, hsv.v);
-  str4 = g_strdup_printf (_("Intensity: %0.3f    Opacity: %0.3f"),
-                          GIMP_RGB_INTENSITY (rgb.r, rgb.g, rgb.b), rgb.a);
+  str4 = g_strdup_printf (_("Luminance: %0.3f    Opacity: %0.3f"),
+                          GIMP_RGB_LUMINANCE (rgb.r, rgb.g, rgb.b), rgb.a);
 
 
   gradient_editor_set_hint (editor, str1, str2, str3, str4);

devel-docs/ChangeLog

+2005-08-03  Sven Neumann  <sven@gimp.org>
+
+	* libgimpcolor/libgimpcolor-sections.txt
+	* libgimpcolor/tmpl/gimprgb.sgml: added gimp_rgb_luminance() and
+	friends.
+
 2005-07-22  Sven Neumann  <sven@gimp.org>
 
 	* libgimpwidgets/libgimpwidgets-sections.txt

devel-docs/libgimpcolor/libgimpcolor-sections.txt

@@ -63,6 +63,8 @@ gimp_rgb_max
 gimp_rgb_min
 gimp_rgb_clamp
 gimp_rgb_gamma
+gimp_rgb_luminance
+gimp_rgb_luminance_uchar
 gimp_rgb_intensity
 gimp_rgb_intensity_uchar
 gimp_rgb_composite
@@ -74,6 +76,10 @@ gimp_rgba_add
 gimp_rgba_subtract
 gimp_rgba_multiply
 gimp_rgba_distance
+GIMP_RGB_LUMINANCE
+GIMP_RGB_LUMINANCE_RED
+GIMP_RGB_LUMINANCE_GREEN
+GIMP_RGB_LUMINANCE_BLUE
 GIMP_RGB_INTENSITY
 GIMP_RGB_INTENSITY_RED
 GIMP_RGB_INTENSITY_GREEN

devel-docs/libgimpcolor/tmpl/gimprgb.sgml

@@ -193,6 +193,24 @@ Definitions and Functions relating to RGB colors.
 @gamma: 
 
 
+<!-- ##### FUNCTION gimp_rgb_luminance ##### -->
+<para>
+
+</para>
+
+@rgb: 
+@Returns: 
+
+
+<!-- ##### FUNCTION gimp_rgb_luminance_uchar ##### -->
+<para>
+
+</para>
+
+@rgb: 
+@Returns: 
+
+
 <!-- ##### FUNCTION gimp_rgb_intensity ##### -->
 <para>
 
@@ -305,6 +323,37 @@ Definitions and Functions relating to RGB colors.
 @Returns: 
 
 
+<!-- ##### MACRO GIMP_RGB_LUMINANCE ##### -->
+<para>
+
+</para>
+
+@r: 
+@g: 
+@b: 
+
+
+<!-- ##### MACRO GIMP_RGB_LUMINANCE_RED ##### -->
+<para>
+
+</para>
+
+
+
+<!-- ##### MACRO GIMP_RGB_LUMINANCE_GREEN ##### -->
+<para>
+
+</para>
+
+
+
+<!-- ##### MACRO GIMP_RGB_LUMINANCE_BLUE ##### -->
+<para>
+
+</para>
+
+
+
 <!-- ##### MACRO GIMP_RGB_INTENSITY ##### -->
 <para>
 This macro calculates the intensity of an RGB value based on

libgimp/gimpdrawable.c

@@ -248,12 +248,12 @@ gimp_drawable_get_color_uchar (gint32         drawable_ID,
       break;
 
     case GIMP_GRAY_IMAGE:
-      color_uchar[0] = gimp_rgb_intensity_uchar (color);
+      color_uchar[0] = gimp_rgb_luminance_uchar (color);
       color_uchar[1] = 255;
       break;
 
     case GIMP_GRAYA_IMAGE:
-      color_uchar[0] = gimp_rgb_intensity_uchar (color);
+      color_uchar[0] = gimp_rgb_luminance_uchar (color);
       gimp_rgba_get_uchar (color, NULL, NULL, NULL, &color_uchar[1]);
       break;
 

libgimp/gimppixelfetcher.c

@@ -160,7 +160,7 @@ gimp_pixel_fetcher_set_bg_color (GimpPixelFetcher *pf,
     {
     case 2: pf->bg_color[1] = 255;
     case 1:
-      pf->bg_color[0] = gimp_rgb_intensity_uchar (color);
+      pf->bg_color[0] = gimp_rgb_luminance_uchar (color);
       break;
 
     case 4: pf->bg_color[3] = 255;

libgimpcolor/gimpcolor.def

@@ -36,6 +36,8 @@ EXPORTS
 	gimp_rgb_intensity
 	gimp_rgb_intensity_uchar
 	gimp_rgb_list_names
+	gimp_rgb_luminance
+	gimp_rgb_luminance_uchar
 	gimp_rgb_max
 	gimp_rgb_min
 	gimp_rgb_multiply

libgimpcolor/gimprgb.c

@@ -25,6 +25,7 @@
 
 #include "gimpcolortypes.h"
 
+#undef GIMP_DISABLE_DEPRECATED  /*  for GIMP_RGB_INTENSITY()  */
 #include "gimprgb.h"
 
 
@@ -228,6 +229,50 @@ gimp_rgb_gamma (GimpRGB *rgb,
   rgb->b = pow (rgb->b, ig);
 }
 
+/**
+ * gimp_rgb_luminance:
+ * @rgb:
+ *
+ * Return value: the luminous intensity of the range from 0.0 to 1.0.
+ *
+ * Since: GIMP 2.4
+ **/
+gdouble
+gimp_rgb_luminance (const GimpRGB *rgb)
+{
+  gdouble luminance;
+
+  g_return_val_if_fail (rgb != NULL, 0.0);
+
+  luminance = GIMP_RGB_LUMINANCE (rgb->r, rgb->g, rgb->b);
+
+  return CLAMP (luminance, 0.0, 1.0);
+}
+
+/**
+ * gimp_rgb_luminance_uchar:
+ * @rgb:
+ *
+ * Return value: the luminous intensity in the range from 0 to 255.
+ *
+ * Since: GIMP 2.4
+ **/
+guchar
+gimp_rgb_luminance_uchar (const GimpRGB *rgb)
+{
+  g_return_val_if_fail (rgb != NULL, 0);
+
+  return ROUND (gimp_rgb_luminance (rgb) * 255.0);
+}
+
+/**
+ * gimp_rgb_intensity:
+ * @rgb:
+ *
+ * This function is deprecated! Use gimp_rgb_luminance() instead.
+ *
+ * Return value: the intensity in the range from 0.0 to 1.0.
+ **/
 gdouble
 gimp_rgb_intensity (const GimpRGB *rgb)
 {
@@ -240,6 +285,14 @@ gimp_rgb_intensity (const GimpRGB *rgb)
   return CLAMP (intensity, 0.0, 1.0);
 }
 
+/**
+ * gimp_rgb_intensity_uchar:
+ * @rgb:
+ *
+ * This function is deprecated! Use gimp_rgb_luminance_uchar() instead.
+ *
+ * Return value: the intensity in the range from 0 to 255.
+ **/
 guchar
 gimp_rgb_intensity_uchar (const GimpRGB *rgb)
 {

libgimpcolor/gimprgb.h

@@ -99,8 +99,13 @@ void      gimp_rgb_clamp       (GimpRGB       *rgb);
 void      gimp_rgb_gamma       (GimpRGB       *rgb,
  			        gdouble        gamma);
 
-gdouble   gimp_rgb_intensity        (const GimpRGB *rgb);
-guchar    gimp_rgb_intensity_uchar  (const GimpRGB *rgb);
+gdouble   gimp_rgb_luminance       (const GimpRGB *rgb);
+guchar    gimp_rgb_luminance_uchar (const GimpRGB *rgb);
+
+#ifndef GIMP_DISABLE_DEPRECATED
+gdouble   gimp_rgb_intensity       (const GimpRGB *rgb);
+guchar    gimp_rgb_intensity_uchar (const GimpRGB *rgb);
+#endif
 
 void      gimp_rgb_composite   (GimpRGB              *color1,
                                 const GimpRGB        *color2,
@@ -146,13 +151,44 @@ gdouble   gimp_rgba_distance   (const GimpRGB *rgba1,
 
 /*  Map RGB to intensity  */
 
-#define GIMP_RGB_INTENSITY_RED    0.30
-#define GIMP_RGB_INTENSITY_GREEN  0.59
-#define GIMP_RGB_INTENSITY_BLUE   0.11
+/*
+ * The weights to compute true CIE luminance from linear red, green
+ * and blue, as defined by the ITU-R Recommendation BT.709, "Basic
+ * Parameter Values for the HDTV Standard for the Studio and for
+ * International Programme Exchange" (1990). Also suggested in the
+ * sRGB colorspace specification by the W3C.
+ */
+
+#define GIMP_RGB_LUMINANCE_RED    (0.2126)
+#define GIMP_RGB_LUMINANCE_GREEN  (0.7152)
+#define GIMP_RGB_LUMINANCE_BLUE   (0.0722)
+
+#define GIMP_RGB_LUMINANCE(r,g,b) ((r) * GIMP_RGB_LUMINANCE_RED   + \
+			           (g) * GIMP_RGB_LUMINANCE_GREEN + \
+			           (b) * GIMP_RGB_LUMINANCE_BLUE)
+
+
+#ifndef GIMP_DISABLE_DEPRECATED
+
+/*
+ * The coefficients below properly computed luminance for monitors
+ * having phosphors that were contemporary at the introduction of NTSC
+ * television in 1953. They are still appropriate for computing video
+ * luma. However, these coefficients do not accurately compute
+ * luminance for contemporary monitors. The use of these definitions
+ * is deprecated.
+ */
+
+#define GIMP_RGB_INTENSITY_RED    (0.30)
+#define GIMP_RGB_INTENSITY_GREEN  (0.59)
+#define GIMP_RGB_INTENSITY_BLUE   (0.11)
+
 #define GIMP_RGB_INTENSITY(r,g,b) ((r) * GIMP_RGB_INTENSITY_RED   + \
 			           (g) * GIMP_RGB_INTENSITY_GREEN + \
 			           (b) * GIMP_RGB_INTENSITY_BLUE)
 
+#endif
+
 
 G_END_DECLS
 

modules/colorsel_triangle.c

@@ -325,7 +325,7 @@ colorsel_triangle_update_preview (ColorselTriangle *triangle)
 
   gimp_hsv_to_rgb4 (buf, atn / (2 * G_PI), 1, 1);
 
-  col = GIMP_RGB_INTENSITY (buf[0], buf[1], buf[2]) > 127 ? 0 : 255;
+  col = GIMP_RGB_LUMINANCE (buf[0], buf[1], buf[2]) > 127 ? 0 : 255;
 
   d = CLAMP (triangle->wheelradius / 16, 2, 4);