change weights to -100.0...+100.0 per cent

The upper and lower horizontal trapeze line will change.
The vertical weight is not implemented now!

3 files changed, 52 insertions, 43 deletions

diff --git a/color_pipe.c b/color_pipe.c
index 648e259..b0a9ddf 100644
--- a/color_pipe.c
+++ b/color_pipe.c
@@ -396,8 +396,8 @@ static void set_default_value(struct color_pipe_t *pipe) {
 	
 	pipe->trapcorr_data.enable = 0;
 	pipe->trapcorr_data.map_init = 0;
-	pipe->trapcorr_data.wv = 1.0f;
-	pipe->trapcorr_data.wh = 1.0f;
+	pipe->trapcorr_data.wv = 0.0f;
+	pipe->trapcorr_data.wh = 0.0f;
 	pipe->trapcorr_data.wv_new = pipe->trapcorr_data.wv;
 	pipe->trapcorr_data.wh_new = pipe->trapcorr_data.wh;
 }
@@ -877,16 +877,15 @@ void __stdcall color_pipe_stageconf_gamma(struct color_pipe_t *color_pipe, int e
 /**
  * Pipeline stage configuration: Isosceles Trapeze Correction
  * 
- * The vertical and horizontal correction weight are positive
- * numbers starting from 0. A weight of 1.0 means no correction. A weight lesser than
- * 1.0 means the upper trapeze line is shorter than the lower trapeze line.
- * Therfore a weight greater than 1.0 means the upper trapeze line is longer than
- * the lower line.
+ * The vertical and horizontal correction weight are per cent values ranging
+ * from -100.0 % to +100.0 %. A positive weight means that the upper horizontal trapeze
+ * is fixed and won't shrink while a negative value means the opposite lower line won't change.
+ * A weight of zero means not correction.
  * 
  * @param color_pipe Pointer to pipeline context
  * @param enable not 0: enable, 0: disable
- * @param wv vertical weight 
- * @param wh horizontal weight
+ * @param wv vertical weight (range: -100.0 to +100.0)
+ * @param wh horizontal weight (range: -100.0 to +100.0)
  */
 void __stdcall color_pipe_stageconf_trapcorr(struct color_pipe_t *color_pipe, int enable, float wv, float wh) {
 	// paranoia
@@ -896,11 +895,18 @@ void __stdcall color_pipe_stageconf_trapcorr(struct color_pipe_t *color_pipe, in
 	}
 	
 	// range check
-	if(wv < 0.0f) {
-		wv = 0.0f;
+	if(wv < -100.0f) {
+		wv = -100.0f;
 	}
-	if(wh < 0.0f) {
-		wh = 0.0f;
+	else if(wv > 100.0) {
+		wv = 100.0f;
+	}
+	
+	if(wh < -100.0f) {
+		wh = -100.0f;
+	}
+	else if(wh > 100.0) {
+		wh = 100.0f;
 	}
 	
 	color_pipe->trapcorr_data.enable = enable;
diff --git a/color_pipe.h b/color_pipe.h
index b4c50da..9b52f23 100644
--- a/color_pipe.h
+++ b/color_pipe.h
@@ -293,10 +293,10 @@ struct trapcorr_data_t {
 	int bit_channel;						///< Bits per color channel.
 	int width;								///< image width in number of pixels
 	int height;								///< image height in number of pixels
-	float wv;								///< vertical correction weight in per cent (NOTE not implemented yet!)
-	float wh;								///< horizontal correction weight in per cent
-	float wv_new;							///< this vertical correction weight in per cent is changed by API call (use double buffering) (NOTE not implemented yet!)
-	float wh_new;							///< this horizontal correction weight in per cent is changed by API call (use double buffering)
+	float wv;								///< vertical correction weight in per cent (range: -100.0 to +100.0) (NOTE not implemented yet!)
+	float wh;								///< horizontal correction weight in per cent (range: -100.0 to +100.0)
+	float wv_new;							///< double buffered vertical correction weight
+	float wh_new;							///< double buffered horizontal correction weight
 	 
 	int map_init;							///< flag indicating perspective correction map is initialized
 	
diff --git a/trapcorr.c b/trapcorr.c
index 3ace25f..aef2411 100644
--- a/trapcorr.c
+++ b/trapcorr.c
@@ -188,7 +188,6 @@ static void correct(struct trapcorr_data_t *data) {
 	const int scale_fact = data->map_scale_fact;
 	const int is_color = data->is_color;
 	
-	
 	for(y = 0; y < height; y++) {
 		for(x = 0; x < width; x++) {
 			x_corr = map->x;
@@ -228,15 +227,32 @@ static void init_map(struct trapcorr_data_t *data) {
 	const int scale_fact = (1 << (data->map_scale_fact));
 	const int width = data->width;
 	const int height = data->height;
-	const float p = data->wh * (width/2.0f);
-	float p_i, row_scale, x_corr, y_corr;
+	float p, p_i, row_scale, x_corr, y_corr;
 	int x_start, x_end;
+	int shrink_upper;
 	
+	// convert -100.0...+100.0 ---> 0.0...2.0
+	const float fact = data->wh/100.0f+1.0f;
 	
-// 	printf("XXX P = %f\n", p);
+	/*
+	 * Checking whether we shrink upper or lower horizontal
+	 * trapeze line.
+	 */ 
+	if(data->wh <= 1.0f) {
+		// upper line shrinks
+		shrink_upper = 1;
+		p = fact * (width/2.0f);
+	}
+	else {
+		// lower line shrinks
+		shrink_upper = 0;
+		p = (2.0f - fact) * (width/2.0f);
+	}
 	
 	/*
-	 * horizontal correction
+	 * We'll loop through image with y-axis symmetrically centered.
+	 * So the image is horizontally shifted to left. Do calculate
+	 * the start and end values on x-axis.
 	 */ 
 	if((width%2) == 0) {
 		// even width
@@ -249,11 +265,15 @@ static void init_map(struct trapcorr_data_t *data) {
 		x_end = (width-1)/2;
 	}
 	
-// 	printf("XXX x_start = %d, x_end = %d, %d x %d\n", x_start,  x_end, width, height);
-	
+	// loop through image
 	for(y = 0; y < height; y++) {
-		
-		p_i = ((width/2.0f - p) / height) * y + p;
+		if(shrink_upper) {
+			p_i = ((width/2.0f - p) / height) * y + p;
+		}
+		else {
+			p_i = (-1.0f*((width/2.0f - p) / height)) * y + width/2.0f;
+		}
+				
 		row_scale = 2.0f * p_i / width;
 		
 		// we don't correct vertically
@@ -262,25 +282,9 @@ static void init_map(struct trapcorr_data_t *data) {
 		for(x = x_start; x <= x_end; x++) {
 			x_corr = x/row_scale;
 			
-// 			if(x > -325 && x < -315 && y < 2) {
-// 				printf("%d/%d: p_i = %f, row_scale = %f, x_corr = %f\n", y, x, p_i, row_scale, x_corr);
-// 			}
-			
 			// trapeze is horizontally symmetrically centered --> shift right
 			x_corr -= x_start;
 			
-// 			if(x > -325 && x < -315 && y < 2) {
-// 				printf("    ----> x_corr (shift)= %f\n", x_corr);
-// 			}
-			
-			// range check
-			if(x_corr < 0.0f) {
-				x_corr = 0.0f;
-			}
-			else if(x_corr > (width-1.0f)) {
-				x_corr = width-1.0f;
-			}
-			
 			// apply scaling factor
 			map->x = (int)roundf(x_corr*scale_fact);
 			map->y = (int)roundf(y_corr*scale_fact);
@@ -305,7 +309,6 @@ int trapcorr(struct trapcorr_data_t *trapcorr_data) {
 		trapcorr_data->map_scale_fact = 9;	// scale by 9 means 2^9 = 512
 		init_map(trapcorr_data);
 		trapcorr_data->map_init = 1;
-		printf("XXXXX map initialized!\n");
 	}
 	
 	// apply perspective correction