[sane-devel] Re: Feature freeze for sane-backends 1.0.13 is active

[Varol Kaptan]

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Here is a patch that fixes color scanning on the EPSON Perfection610. It is
based on the epkowa backend (but done in a cleaner way). It works for me -
and most probably does not break anything else. Can people with epson
scanners check it?

Varol Kaptan
varol@cs.ucf.edu

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--- epson.c.orig	2003-11-04 14:58:39.000000000 -0500
+++ epson.c	2003-11-04 14:59:00.000000000 -0500
@@ -4089,24 +4089,6 @@
 	s->params.pixels_per_line = SANE_UNFIX( s->val[ OPT_BR_X].w -  s->val[ OPT_TL_X].w) / 25.4 * ndpi + 0.5;
 	s->params.lines = SANE_UNFIX( s->val[ OPT_BR_Y].w - s->val[ OPT_TL_Y].w) / 25.4 * ndpi + 0.5;
 
-	/* 
-	 * Make sure that the number of lines is correct for color shuffling:
-	 * The shuffling alghorithm produces 2xline_distance lines at the
-	 * beginning and the same amount at the end of the scan that are not
-	 * useable. If s->params.lines gets negative, 0 lines are reported
-	 * back to the frontend.
-	 */
-	if (s->hw->color_shuffle)
-	{
-		s->params.lines -= 4*s->line_distance;
-		if (s->params.lines < 0)
-		{
-			s->params.lines = 0;
-		}
-		DBG(1, "Adjusted params.lines for color_shuffle by %d to %d\n", 
-				4*s->line_distance, s->params.lines);
-	}
-
 	DBG( 3, "Preview = %d\n", s->val[OPT_PREVIEW].w);
 	DBG( 3, "Resolution = %d\n", s->val[OPT_RESOLUTION].w);
 
@@ -4630,41 +4612,18 @@
 	s->hw->color_shuffle = SANE_TRUE;
 #endif
 
-
   /* 
    * Modify the scan area: If the scanner requires color shuffling, then we try to
    * scan more lines to compensate for the lines that will be removed from the scan
    * due to the color shuffling alghorithm.
-   * At this time we add two times the line distance to the number of scan lines if
-   * this is possible - if not, then we try to calculate the number of additional
-   * lines according to the selected scan area.
+   * At this time we add two times the line distance to the number of scan lines.
    */
 	if (s->hw->color_shuffle == SANE_TRUE) 
-	{
-
-		/* start the scan 2*line_distance earlier */
-		top -= 2*s->line_distance;
-		if (top < 0)
-		{
-			top = 0;
-		}
-
-		/* scan 4*line_distance lines more */
-		s->params.lines += 4*s->line_distance;
-	}
-
-	/* 
-	 * If (top + s->params.lines) is larger than the max scan area, reset
-	 * the number of scan lines:
-	 */
-	if (SANE_UNFIX( s->val[ OPT_BR_Y].w) / 25.4 * ndpi < (s->params.lines + top))
-	{
-		s->params.lines = ((int) SANE_UNFIX(s->val[OPT_BR_Y].w) / 
-				25.4 * ndpi + 0.5) - top;
-	}
-
+		s->extra_lines = 2*s->line_distance;
+	else
+		s->extra_lines = 0;
 
-	status = set_scan_area(s, left, top, s->params.pixels_per_line, s->params.lines);
+	status = set_scan_area(s, left, top, s->params.pixels_per_line, s->params.lines + s->extra_lines);
 
 	if( SANE_STATUS_GOOD != status) 
 	{
@@ -5045,7 +5004,7 @@
 			if (s->hw->color_shuffle) 
 			{
 				DBG(1, "Written %d lines after color shuffle\n", s->lines_written);
-				DBG(1, "Lines requested: %d\n", s->params.lines);
+				DBG(1, "Lines requested: %d\n", s->params.lines + s->extra_lines);
 			}
 
 			*length = 0;
@@ -5506,6 +5465,7 @@
 			}
 
 			data_ptr += s->params.bytes_per_line;
+			s->ptr += s->params.bytes_per_line;
 
 			if (s->color_shuffle_line == s->line_distance)
 			{
--- epson.h.orig	2003-11-04 14:58:45.000000000 -0500
+++ epson.h	2003-11-04 15:02:51.000000000 -0500
@@ -271,6 +271,7 @@
 	SANE_Option_Descriptor opt [ NUM_OPTIONS];
 	Option_Value val [ NUM_OPTIONS];
 	SANE_Parameters params;
+	SANE_Int extra_lines;		/* extra lines to read for color shuffle */
 	SANE_Bool block;
 	SANE_Bool eof;
 	SANE_Byte * buf, * end, * ptr;

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