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

[Varol Kaptan]

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Here is a good patch (I did an extensive set of tests to make 
sure it is working as intended)

Varol

On Tue, Nov 04, 2003 at 03:47:43PM -0500, khk@khk.net wrote:
> You basically disabled the error checks for a negative number of
> scan lines and the case where more scan lines as the scanner can support
> are requested. This is not acceptable - the checks are there for
> a reason. You are certainly free to use a modified backend with
> your scanner, but I will not apply your patch to the CVS version.
> 
> Karl Heinz

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--- epson.c.orig	2003-11-04 17:07:40.000000000 -0500
+++ epson.c	2003-11-04 19:39:08.000000000 -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 +4612,35 @@
 	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;
-	}
+		s->extra_lines = 2*s->line_distance;
+	else
+		s->extra_lines = 0;
 
 	/* 
-	 * If (top + s->params.lines) is larger than the max scan area, reset
-	 * the number of scan lines:
+	 * If (top + s->params.lines + s->extra_lines) is larger than the max scan 
+	 * area, adjust 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;
-	}
+		SANE_Int cur_br_y, max_br_y;
 
+		max_br_y = (SANE_Int) (SANE_UNFIX(s->hw->y_range->max) / 25.4 * ndpi + 0.5); 
+		cur_br_y = top + s->params.lines + s->extra_lines;
+		
+		if (max_br_y < cur_br_y)
+		{
+			s->params.lines = (max_br_y - s->extra_lines) - top;
+			DBG( 5, "sane_start: adjusting lines to %d\n", s->params.lines);
+		}
+	}
 
-	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 +5021,7 @@
 			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 +5482,7 @@
 			}
 
 			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 17:07:43.000000000 -0500
+++ epson.h	2003-11-04 18:02:15.000000000 -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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