1 files changed, 46 insertions, 22 deletions
diff --git a/draw/draw_simple_scale.c b/draw/draw_simple_scale.c
index 178b182f..cb419126 100644
--- a/draw/draw_simple_scale.c
+++ b/draw/draw_simple_scale.c
@@ -218,16 +218,17 @@ typedef struct fz_weights_s fz_weights;
 
 struct fz_weights_s
 {
-	int flip;
-	int count;
-	int max_len;
-	int n;
-	int new_line;
+	int flip;	/* true if outputting reversed */
+	int count;	/* number of output pixels we have records for in this table */
+	int max_len;	/* Maximum number of weights for any one output pixel */
+	int n;		/* number of components (src->n) */
+	int new_line;	/* True if no weights for the current output pixel */
+	int patch_l;    /* How many output pixels we skip over */
 	int index[1];
 };
 
 static fz_weights *
-new_weights(fz_context *ctx, fz_scale_filter *filter, int src_w, float dst_w, int dst_w_i, int n, int flip)
+new_weights(fz_context *ctx, fz_scale_filter *filter, int src_w, float dst_w, int patch_w, int n, int flip, int patch_l)
 {
 	int max_len;
 	fz_weights *weights;
@@ -249,26 +250,29 @@ new_weights(fz_context *ctx, fz_scale_filter *filter, int src_w, float dst_w, in
 		max_len = 2 * filter->width;
 	}
 	/* We need the size of the struct,
-	 * plus dst_w*sizeof(int) for the index
+	 * plus patch_w*sizeof(int) for the index
 	 * plus (2+max_len)*sizeof(int) for the weights
 	 * plus room for an extra set of weights for reordering.
 	 */
-	weights = fz_malloc(ctx, sizeof(*weights)+(max_len+3)*(dst_w_i+1)*sizeof(int));
+	weights = fz_malloc(ctx, sizeof(*weights)+(max_len+3)*(patch_w+1)*sizeof(int));
 	if (!weights)
 		return NULL;
 	weights->count = -1;
 	weights->max_len = max_len;
-	weights->index[0] = dst_w_i;
+	weights->index[0] = patch_w;
 	weights->n = n;
+	weights->patch_l = patch_l;
 	weights->flip = flip;
 	return weights;
 }
 
+/* j is destination pixel in the patch_l..patch_l+patch_w range */
 static void
 init_weights(fz_weights *weights, int j)
 {
 	int index;
 
+	j -= weights->patch_l;
 	assert(weights->count == j-1);
 	weights->count++;
 	weights->new_line = 1;
@@ -316,6 +320,8 @@ add_weight(fz_weights *weights, int j, int i, fz_scale_filter *filter,
 
 	DBUG(("add_weight[%d][%d] = %d(%g) dist=%g\n",j,i,weight,f,dist));
 
+	/* Move j from patch_l...patch_l+patch_w range to 0..patch_w range */
+	j -= weights->patch_l;
 	if (weights->new_line)
 	{
 		/* New line */
@@ -366,7 +372,7 @@ add_weight(fz_weights *weights, int j, int i, fz_scale_filter *filter,
 static void
 reorder_weights(fz_weights *weights, int j, int src_w)
 {
-	int idx = weights->index[j];
+	int idx = weights->index[j - weights->patch_l];
 	int min = weights->index[idx++];
 	int len = weights->index[idx++];
 	int max = weights->max_len;
@@ -413,7 +419,7 @@ check_weights(fz_weights *weights, int j, int w, float x, float wf)
 	int maxidx = 0;
 	int i;
 
-	idx = weights->index[j];
+	idx = weights->index[j - weights->patch_l];
 	idx++; /* min */
 	len = weights->index[idx++];
 
@@ -443,7 +449,7 @@ check_weights(fz_weights *weights, int j, int w, float x, float wf)
 }
 
 static fz_weights *
-make_weights(fz_context *ctx, int src_w, float x, float dst_w, fz_scale_filter *filter, int vertical, int dst_w_int, int n, int flip)
+make_weights(fz_context *ctx, int src_w, float x, float dst_w, fz_scale_filter *filter, int vertical, int patch_l, int patch_r, int n, int flip)
 {
 	fz_weights *weights;
 	float F, G;
@@ -463,11 +469,11 @@ make_weights(fz_context *ctx, int src_w, float x, float dst_w, fz_scale_filter *
 		G = src_w / dst_w;
 	}
 	window = filter->width / F;
-	DBUG(("make_weights src_w=%d x=%g dst_w=%g dst_w_int=%d F=%g window=%g\n", src_w, x, dst_w, dst_w_int, F, window));
-	weights	= new_weights(ctx, filter, src_w, dst_w, dst_w_int, n, flip);
+	DBUG(("make_weights src_w=%d x=%g dst_w=%g patch_l=%d patch_r=%d F=%g window=%g\n", src_w, x, dst_w, patch_l, patch_r, F, window));
+	weights	= new_weights(ctx, filter, src_w, dst_w, patch_r-patch_l, n, flip, patch_l);
 	if (!weights)
 		return NULL;
-	for (j = 0; j < dst_w_int; j++)
+	for (j = patch_l; j < patch_r; j++)
 	{
 		/* find the position of the centre of dst[j] in src space */
 		float centre = (j - x + 0.5f)*src_w/dst_w - 0.5f;
@@ -480,7 +486,7 @@ make_weights(fz_context *ctx, int src_w, float x, float dst_w, fz_scale_filter *
 		{
 			add_weight(weights, j, l, filter, x, F, G, src_w, dst_w);
 		}
-		check_weights(weights, j, dst_w_int, x, dst_w);
+		check_weights(weights, j, patch_r-patch_l, x, dst_w);
 		if (vertical)
 		{
 			reorder_weights(weights, j, src_w);
@@ -1167,7 +1173,7 @@ scale_single_col(unsigned char *dst, unsigned char *src, fz_weights *weights, in
 #endif /* SINGLE_PIXEL_SPECIALS */
 
 fz_pixmap *
-fz_scale_pixmap(fz_context *ctx, fz_pixmap *src, float x, float y, float w, float h)
+fz_scale_pixmap(fz_context *ctx, fz_pixmap *src, float x, float y, float w, float h, fz_bbox *clip)
 {
 	fz_scale_filter *filter = &fz_scale_filter_simple;
 	fz_weights *contrib_rows = NULL;
@@ -1177,6 +1183,7 @@ fz_scale_pixmap(fz_context *ctx, fz_pixmap *src, float x, float y, float w, floa
 	int max_row, temp_span, temp_rows, row;
 	int dst_w_int, dst_h_int, dst_x_int, dst_y_int;
 	int flip_x, flip_y;
+	fz_bbox patch;
 
 	fz_var(contrib_cols);
 	fz_var(contrib_rows);
@@ -1245,21 +1252,38 @@ fz_scale_pixmap(fz_context *ctx, fz_pixmap *src, float x, float y, float w, floa
 
 	fz_try(ctx)
 	{
+		/* Step 0: Calculate the patch */
+		patch.x0 = 0;
+		patch.y0 = 0;
+		patch.x1 = dst_w_int;
+		patch.y1 = dst_h_int;
+		if (clip)
+		{
+			if (patch.x0 < clip->x0 - dst_x_int)
+				patch.x0 = clip->x0 - dst_x_int;
+			if (patch.x1 > clip->x1 - dst_x_int)
+				patch.x1 = clip->x1 - dst_x_int;
+			if (patch.y0 < clip->y0 - dst_y_int)
+				patch.y0 = clip->y0 - dst_y_int;
+			if (patch.y1 > clip->y1 - dst_y_int)
+				patch.y1 = clip->y1 - dst_y_int;
+		}
+
 		/* Step 1: Calculate the weights for columns and rows */
 #ifdef SINGLE_PIXEL_SPECIALS
 		if (src->w == 1)
 			contrib_cols = NULL;
 		else
 #endif /* SINGLE_PIXEL_SPECIALS */
-			contrib_cols = make_weights(ctx, src->w, x, w, filter, 0, dst_w_int, src->n, flip_x);
+			contrib_cols = make_weights(ctx, src->w, x, w, filter, 0, patch.x0, patch.x1, src->n, flip_x);
 #ifdef SINGLE_PIXEL_SPECIALS
 		if (src->h == 1)
 			contrib_rows = NULL;
 		else
 #endif /* SINGLE_PIXEL_SPECIALS */
-			contrib_rows = make_weights(ctx, src->h, y, h, filter, 1, dst_h_int, src->n, flip_y);
+			contrib_rows = make_weights(ctx, src->h, y, h, filter, 1, patch.y0, patch.y1, src->n, flip_y);
 
-		output = fz_new_pixmap(ctx, src->colorspace, dst_w_int, dst_h_int);
+		output = fz_new_pixmap(ctx, src->colorspace, patch.x1-patch.x0, patch.y1-patch.y0);
 	}
 	fz_catch(ctx)
 	{
@@ -1267,8 +1291,8 @@ fz_scale_pixmap(fz_context *ctx, fz_pixmap *src, float x, float y, float w, floa
 		fz_free(ctx, contrib_rows);
 		fz_rethrow(ctx);
 	}
-	output->x = dst_x_int;
-	output->y = dst_y_int;
+	output->x = dst_x_int + patch.x0;
+	output->y = dst_y_int + patch.y0;
 
 	/* Step 2: Apply the weights */
 #ifdef SINGLE_PIXEL_SPECIALS