Rework clip handling. The clip rectangle and the origin of drawing

are now two different things, so that you can clip drawing within
changing your coordinate system.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

6 files changed, 138 insertions, 29 deletions

diff --git a/twin.h b/twin.h
index c2603c6..2e13fe0 100644
--- a/twin.h
+++ b/twin.h
@@ -117,9 +117,13 @@ typedef struct _twin_pixmap {
 
     /*
      * Clipping - a single rectangle in pixmap coordinates.
-     * Drawing is done relative to this rectangle
+     * Drawing is done clipped by this rectangle and relative
+     * to origin_x, origin_y
      */
     twin_rect_t			clip;
+    twin_coord_t		origin_x;
+    twin_coord_t		origin_y;
+
     /*
      * Pixels
      */
@@ -955,15 +959,35 @@ void
 twin_pixmap_disable_update (twin_pixmap_t *pixmap);
 
 void
-twin_pixmap_clip (twin_pixmap_t *pixmap,
+twin_pixmap_get_origin (twin_pixmap_t *pixmap,
+			twin_coord_t *ox, twin_coord_t *oy);
+
+void
+twin_pixmap_set_origin (twin_pixmap_t *pixmap,
+			twin_coord_t ox, twin_coord_t oy);
+
+void
+twin_pixmap_origin_to_clip (twin_pixmap_t *pixmap);
+
+void
+twin_pixmap_offset (twin_pixmap_t *pixmap,
+		    twin_coord_t offx, twin_coord_t offy);
+
+
+void
+twin_pixmap_clip (twin_pixmap_t	*pixmap,
 		  twin_coord_t	left,	twin_coord_t top,
 		  twin_coord_t	right,	twin_coord_t bottom);
 
 void
 twin_pixmap_set_clip (twin_pixmap_t *pixmap, twin_rect_t clip);
 
+
+twin_rect_t
+twin_pixmap_get_clip (twin_pixmap_t *pixmap);
+
 twin_rect_t
-twin_pixmap_current_clip (twin_pixmap_t *pixmap);
+twin_pixmap_save_clip (twin_pixmap_t *pixmap);
 
 void
 twin_pixmap_restore_clip (twin_pixmap_t *pixmap, twin_rect_t rect);
diff --git a/twin_box.c b/twin_box.c
index b1aa299..72ed5e1 100644
--- a/twin_box.c
+++ b/twin_box.c
@@ -230,17 +230,21 @@ _twin_box_dispatch (twin_widget_t *widget, twin_event_t *event)
 	    if (child->paint)
 	    {
 		twin_pixmap_t	*pixmap = box->widget.window->pixmap;
-		twin_rect_t	clip = twin_pixmap_current_clip (pixmap);
+		twin_rect_t	clip = twin_pixmap_save_clip (pixmap);
+		twin_coord_t	ox, oy;
 
+		twin_pixmap_get_origin (pixmap, &ox, &oy);
 		if (child->shape != TwinShapeRectangle)
 		    twin_fill (child->window->pixmap,
 			       widget->background, TWIN_SOURCE,
 			       child->extents.left, child->extents.top,
 			       child->extents.right, child->extents.bottom);
 		twin_pixmap_set_clip (pixmap, child->extents);
+		twin_pixmap_origin_to_clip (pixmap);
 		child->paint = TWIN_FALSE;
 		(*child->dispatch) (child, event);
 		twin_pixmap_restore_clip (pixmap, clip);
+		twin_pixmap_set_origin (pixmap, ox, oy);
 	    }
 	break;
     default:
diff --git a/twin_draw.c b/twin_draw.c
index 3045cea..48a9da6 100644
--- a/twin_draw.c
+++ b/twin_draw.c
@@ -276,8 +276,8 @@ static void _twin_composite_simple (twin_pixmap_t	*dst,
     twin_coord_t    sdx, sdy;
     twin_source_u   s;
 
-    dst_x += dst->clip.left;
-    dst_y += dst->clip.top;
+    dst_x += dst->origin_x;
+    dst_y += dst->origin_y;
     left = dst_x;
     top = dst_y;
     right = dst_x + width;
@@ -296,7 +296,10 @@ static void _twin_composite_simple (twin_pixmap_t	*dst,
     if (left >= right || top >= bottom)
 	return;
 
-    if (src->source_kind != TWIN_PIXMAP)
+    if (src->source_kind == TWIN_PIXMAP) {
+	src_x += src->u.pixmap->origin_x;
+	src_y += src->u.pixmap->origin_y;
+    } else
         s.c = src->u.argb;
     
     sdx = src_x - dst_x;
@@ -307,7 +310,10 @@ static void _twin_composite_simple (twin_pixmap_t	*dst,
 	twin_source_u   m;
 	twin_coord_t	mdx, mdy;
 	
-	if (msk->source_kind != TWIN_PIXMAP)
+	if (msk->source_kind == TWIN_PIXMAP) {
+	    msk_x += msk->u.pixmap->origin_x;
+	    msk_y += msk->u.pixmap->origin_y;
+	} else
 	    m.c = msk->u.argb;
 	
 	mdx = msk_x - dst_x;
@@ -533,8 +539,8 @@ static void _twin_composite_xform (twin_pixmap_t	*dst,
     twin_xform_t    *sxform = NULL, *mxform = NULL;
     twin_source_u   s;
 
-    dst_x += dst->clip.left;
-    dst_y += dst->clip.top;
+    dst_x += dst->origin_x;
+    dst_y += dst->origin_y;
     left = dst_x;
     top = dst_y;
     right = dst_x + width;
@@ -556,7 +562,9 @@ static void _twin_composite_xform (twin_pixmap_t	*dst,
     width = right - left;
     height = bottom - top;
 
-    if (src->source_kind == TWIN_PIXMAP) {
+    if (src->source_kind == TWIN_PIXMAP) {	
+	src_x += src->u.pixmap->origin_x;
+	src_y += src->u.pixmap->origin_y;
 	sxform = twin_pixmap_init_xform(src->u.pixmap, left, width,
 					src_x, src_y);
 	if (sxform == NULL)
@@ -570,6 +578,8 @@ static void _twin_composite_xform (twin_pixmap_t	*dst,
 	twin_source_u   m;
 	
 	if (msk->source_kind == TWIN_PIXMAP) {
+	    msk_x += msk->u.pixmap->origin_x;
+	    msk_y += msk->u.pixmap->origin_y;
 	    mxform = twin_pixmap_init_xform(msk->u.pixmap, left, width,
 					    msk_x, msk_y);
 	    if (mxform == NULL)
@@ -660,11 +670,13 @@ twin_fill (twin_pixmap_t    *dst,
     twin_src_op	    op;
     twin_source_u   src;
     twin_coord_t    iy;
-    
-    left += dst->clip.left;
-    right += dst->clip.left;
-    top += dst->clip.top;
-    bottom += dst->clip.top;
+
+    /* offset */
+    left += dst->origin_x;
+    top += dst->origin_y;
+    right += dst->origin_x;
+    bottom += dst->origin_y;
+
     /* clip */
     if (left < dst->clip.left)
 	left = dst->clip.left;
diff --git a/twin_pixmap.c b/twin_pixmap.c
index b390ad6..e056093 100644
--- a/twin_pixmap.c
+++ b/twin_pixmap.c
@@ -43,6 +43,7 @@ twin_pixmap_create (twin_format_t   format,
     pixmap->clip.left = pixmap->clip.top = 0;
     pixmap->clip.right = pixmap->width;
     pixmap->clip.bottom = pixmap->height;
+    pixmap->origin_x = pixmap->origin_y = 0;
     pixmap->stride = stride;
     pixmap->disable = 0;
     pixmap->p.v = pixmap + 1;
@@ -71,6 +72,7 @@ twin_pixmap_create_const (twin_format_t	    format,
     pixmap->clip.left = pixmap->clip.top = 0;
     pixmap->clip.right = pixmap->width;
     pixmap->clip.bottom = pixmap->height;
+    pixmap->origin_x = pixmap->origin_y = 0;
     pixmap->stride = stride;
     pixmap->disable = 0;
     pixmap->p = pixels;
@@ -184,32 +186,90 @@ twin_pixmap_disable_update (twin_pixmap_t *pixmap)
 }
 
 void
+twin_pixmap_set_origin (twin_pixmap_t *pixmap,
+			twin_coord_t ox, twin_coord_t oy)
+{
+	pixmap->origin_x = ox;
+	pixmap->origin_y = oy;
+}
+
+void
+twin_pixmap_offset (twin_pixmap_t *pixmap,
+		    twin_coord_t offx, twin_coord_t offy)
+{
+	pixmap->origin_x += offx;
+	pixmap->origin_y += offy;
+}
+
+void
+twin_pixmap_get_origin (twin_pixmap_t *pixmap,
+			twin_coord_t *ox, twin_coord_t *oy)
+{
+    *ox = pixmap->origin_x;
+    *oy = pixmap->origin_y;
+}
+
+void
+twin_pixmap_origin_to_clip (twin_pixmap_t *pixmap)
+{
+    pixmap->origin_x = pixmap->clip.left;
+    pixmap->origin_y = pixmap->clip.top;
+}
+
+void
 twin_pixmap_clip (twin_pixmap_t *pixmap,
 		  twin_coord_t	left,	twin_coord_t top,
 		  twin_coord_t	right,	twin_coord_t bottom)
 {
+    left += pixmap->origin_x;
+    right += pixmap->origin_x;
+    top += pixmap->origin_y;
+    bottom += pixmap->origin_y;
+
     if (left > pixmap->clip.left)	pixmap->clip.left = left;
     if (top > pixmap->clip.top)		pixmap->clip.top = top;
     if (right < pixmap->clip.right)	pixmap->clip.right = right;
     if (bottom < pixmap->clip.bottom)	pixmap->clip.bottom = bottom;
+
     if (pixmap->clip.left >= pixmap->clip.right)
 	pixmap->clip.right = pixmap->clip.left = 0;
     if (pixmap->clip.top >= pixmap->clip.bottom)
 	pixmap->clip.bottom = pixmap->clip.top = 0;
+
+    if (pixmap->clip.left < 0)
+	pixmap->clip.left = 0;
+    if (pixmap->clip.top < 0)
+	pixmap->clip.top = 0;
+    if (pixmap->clip.right > pixmap->width)
+	pixmap->clip.right = pixmap->width;
+    if (pixmap->clip.bottom > pixmap->height)
+	pixmap->clip.bottom = pixmap->height;
 }
 
 void
 twin_pixmap_set_clip (twin_pixmap_t *pixmap, twin_rect_t clip)
 {
     twin_pixmap_clip (pixmap, 
-		      clip.left  + pixmap->clip.left,
-		      clip.top   + pixmap->clip.top,
-		      clip.right + pixmap->clip.left,
-		      clip.bottom+ pixmap->clip.top);
+		      clip.left, clip.top,
+		      clip.right, clip.bottom);
+}
+
+
+twin_rect_t
+twin_pixmap_get_clip (twin_pixmap_t *pixmap)
+{
+    twin_rect_t clip = pixmap->clip;
+
+    clip.left -= pixmap->origin_x;
+    clip.right -= pixmap->origin_x;
+    clip.top -= pixmap->origin_y;
+    clip.bottom -= pixmap->origin_y;
+
+    return clip;
 }
 
 twin_rect_t
-twin_pixmap_current_clip (twin_pixmap_t *pixmap)
+twin_pixmap_save_clip (twin_pixmap_t *pixmap)
 {
     return pixmap->clip;
 }
diff --git a/twin_poly.c b/twin_poly.c
index 16c2b1f..71e5578 100644
--- a/twin_poly.c
+++ b/twin_poly.c
@@ -206,8 +206,8 @@ _span_fill (twin_pixmap_t   *pixmap,
     if (left < twin_int_to_sfixed (pixmap->clip.left))
 	left = twin_int_to_sfixed (pixmap->clip.left);
     
-    if (right > twin_int_to_sfixed (pixmap->width))
-	right = twin_int_to_sfixed (pixmap->width);
+    if (right > twin_int_to_sfixed (pixmap->clip.right))
+	right = twin_int_to_sfixed (pixmap->clip.right);
 
     /* convert to sample grid */
     left = _twin_sfixed_grid_ceil (left) >> TWIN_POLY_FIXED_SHIFT;
@@ -353,15 +353,13 @@ twin_fill_path (twin_pixmap_t *pixmap, twin_path_t *path,
     int		    nalloc;
     int		    s;
     int		    p;
-    twin_sfixed_t   sdx = twin_int_to_sfixed (dx);
-    twin_sfixed_t   sdy = twin_int_to_sfixed (dy);
+    twin_sfixed_t   sdx = twin_int_to_sfixed (dx + pixmap->origin_x);
+    twin_sfixed_t   sdy = twin_int_to_sfixed (dy + pixmap->origin_y);
 
     nalloc = path->npoints + path->nsublen + 1;
     edges = malloc (sizeof (twin_edge_t) * nalloc);
     p = 0;
     nedges = 0;
-    dx += twin_int_to_sfixed (pixmap->clip.left);
-    dy += twin_int_to_sfixed (pixmap->clip.top);
     for (s = 0; s <= path->nsublen; s++)
     {
 	int sublen;
@@ -375,7 +373,8 @@ twin_fill_path (twin_pixmap_t *pixmap, twin_path_t *path,
 	if (npoints > 1)
 	{
 	    n = _twin_edge_build (path->points + p, npoints, edges + nedges,
-				  sdx, sdy, twin_int_to_sfixed (pixmap->clip.top));
+				  sdx, sdy,
+				  twin_int_to_sfixed (pixmap->clip.top));
 	    p = sublen;
 	    nedges += n;
 	}
diff --git a/twin_window.c b/twin_window.c
index d4c69c7..ff2862f 100644
--- a/twin_window.c
+++ b/twin_window.c
@@ -70,6 +70,7 @@ twin_window_create (twin_screen_t	*screen,
     twin_pixmap_clip (window->pixmap,
 		      window->client.left, window->client.top,
 		      window->client.right, window->client.bottom);
+    twin_pixmap_origin_to_clip (window->pixmap);
     window->pixmap->window = window;
     twin_pixmap_move (window->pixmap, x, y);
     window->damage.left = window->damage.right = 0;
@@ -136,9 +137,11 @@ twin_window_configure (twin_window_t	    *window,
 	for (i = 0; i < old->disable; i++)
 	    twin_pixmap_disable_update (window->pixmap);
 	twin_pixmap_destroy (old);
+	twin_pixmap_reset_clip (window->pixmap);
 	twin_pixmap_clip (window->pixmap,
 			  window->client.left, window->client.top,
 			  window->client.right, window->client.bottom);
+	twin_pixmap_origin_to_clip (window->pixmap);
     }
     if (x != window->pixmap->x || y != window->pixmap->y)
 	twin_pixmap_move (window->pixmap, x, y);
@@ -207,6 +210,7 @@ twin_window_frame (twin_window_t *window)
     const char		*name;
     
     twin_pixmap_reset_clip (pixmap);
+    twin_pixmap_origin_to_clip (pixmap);
     
     twin_fill (pixmap, 0x00000000, TWIN_SOURCE, 
 	       0, 0, pixmap->width, window->client.top);
@@ -264,12 +268,14 @@ twin_window_frame (twin_window_t *window)
 		      0,
 		      twin_fixed_to_int (twin_fixed_ceil (c_right - t_arc_2)),
 		      window->client.top);
-    
+    twin_pixmap_origin_to_clip (pixmap);
+
     twin_path_move (path, text_x - twin_fixed_floor (menu_x), text_y);
     twin_path_utf8 (path, window->name);
     twin_paint_path (pixmap, TWIN_FRAME_TEXT, path);
 
     twin_pixmap_reset_clip (pixmap);
+    twin_pixmap_origin_to_clip (pixmap);
 	
     /* widgets */
 
@@ -307,12 +313,16 @@ twin_window_frame (twin_window_t *window)
     twin_pixmap_clip (pixmap,
 		      window->client.left, window->client.top,
 		      window->client.right, window->client.bottom);
+    twin_pixmap_origin_to_clip (pixmap);
+
     twin_path_destroy (path);
 }
 
 void
 twin_window_draw (twin_window_t *window)
 {
+    twin_pixmap_t *pixmap = window->pixmap;
+
     switch (window->style) {
     case TwinWindowPlain:
     default: