--- ImageMagick-6.1.3/coders/jp2.c_orig	2004-11-03 14:48:28.000000000 +0100
+++ ImageMagick-6.1.3/coders/jp2.c	2004-11-03 14:50:49.000000000 +0100
@@ -298,6 +298,8 @@
 
   unsigned int
     channel_scale[4],
+    channel_step_x[4],
+    channel_step_y[4],
     maximum_component_depth;
 
   unsigned long
@@ -407,18 +409,20 @@
   image->rows=jas_image_height(jp2_image);
   for (i=0; i < (long) number_components; i++)
   {
-    if ((jas_image_cmptwidth(jp2_image,components[i]) != image->columns) ||
-        (jas_image_cmptheight(jp2_image,components[i]) != image->rows) ||
+    if (((jas_image_cmptwidth(jp2_image,components[i]) *
+          jas_image_cmpthstep(jp2_image,components[i])) != image->columns) ||
+        ((jas_image_cmptheight(jp2_image,components[i]) *
+          jas_image_cmptvstep(jp2_image,components[i])) != image->rows) ||
         (jas_image_cmpttlx(jp2_image,components[i]) != 0) ||
         (jas_image_cmpttly(jp2_image,components[i]) != 0) ||
-        (jas_image_cmpthstep(jp2_image,components[i]) != 1) ||
-        (jas_image_cmptvstep(jp2_image,components[i]) != 1) ||
         (jas_image_cmptsgnd(jp2_image,components[i]) != MagickFalse))
       {
         (void) jas_stream_close(jp2_stream);
         jas_image_destroy(jp2_image);
         ThrowReaderException(CoderError,"IrregularChannelGeometryNotSupported");
       }
+    channel_step_x[i] = jas_image_cmpthstep(jp2_image,components[i]);
+    channel_step_y[i] = jas_image_cmptvstep(jp2_image,components[i]);
   }
   /*
     Convert JPEG 2000 pixels.
@@ -435,7 +439,7 @@
   {
     maximum_component_depth=Max(jas_image_cmptprec(jp2_image,components[i]),
       maximum_component_depth);
-    pixels[i]=jas_matrix_create(1,(unsigned int) image->columns);
+    pixels[i]=jas_matrix_create(1,((unsigned int) image->columns)/channel_step_x[i]);
     if (pixels[i] == (jas_matrix_t *) NULL)
       {
         jas_image_destroy(jp2_image);
@@ -467,7 +471,7 @@
       break;
     for (i=0; i < (long) number_components; i++)
       (void) jas_image_readcmpt(jp2_image,(short) components[i],0,
-         (unsigned int) y,(unsigned int) image->columns,1,pixels[i]);
+         ((unsigned int) y)/channel_step_y[i],((unsigned int) image->columns)/channel_step_x[i],1,pixels[i]);
     switch (number_components)
     {
       case 1:
@@ -494,7 +498,7 @@
         else
           for (x=0; x < (long) image->columns; x++)
           {
-            index=(unsigned short) jas_matrix_getv(pixels[0],x)*
+            index=(unsigned short) jas_matrix_getv(pixels[0],(x/channel_step_x[0]))*
               channel_scale[0];
             index=ConstrainColormapIndex(image,index);
             *indexes++=index;
@@ -510,11 +514,11 @@
         for (x=0; x < (long) image->columns; x++)
         {
           q->red=ScaleShortToQuantum((unsigned short)
-            jas_matrix_getv(pixels[0],x)*channel_scale[0]);
+            jas_matrix_getv(pixels[0],(x/channel_step_x[0]))*channel_scale[0]);
           q->green=ScaleShortToQuantum((unsigned short)
-            jas_matrix_getv(pixels[1],x)*channel_scale[1]);
+            jas_matrix_getv(pixels[1],(x/channel_step_x[1]))*channel_scale[1]);
           q->blue=ScaleShortToQuantum((unsigned short)
-            jas_matrix_getv(pixels[2],x)*channel_scale[2]);
+            jas_matrix_getv(pixels[2],(x/channel_step_x[2]))*channel_scale[2]);
           q++;
         }
         break;
@@ -527,13 +531,13 @@
         for (x=0; x < (long) image->columns; x++)
         {
           q->red=ScaleShortToQuantum((unsigned short)
-            jas_matrix_getv(pixels[0],x)*channel_scale[0]);
+            jas_matrix_getv(pixels[0],(x/channel_step_x[0]))*channel_scale[0]);
           q->green=ScaleShortToQuantum((unsigned short)
-            jas_matrix_getv(pixels[1],x)*channel_scale[1]);
+            jas_matrix_getv(pixels[1],(x/channel_step_x[1]))*channel_scale[1]);
           q->blue=ScaleShortToQuantum((unsigned short)
-            jas_matrix_getv(pixels[2],x)*channel_scale[2]);
+            jas_matrix_getv(pixels[2],(x/channel_step_x[2]))*channel_scale[2]);
           q->opacity=MaxRGB-ScaleShortToQuantum((unsigned short)
-            jas_matrix_getv(pixels[3],x)*channel_scale[3]);
+            jas_matrix_getv(pixels[3],(x/channel_step_x[3]))*channel_scale[3]);
           q++;
         }
         break;