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-rw-r--r--src/display/canvas-text.cpp88
1 files changed, 60 insertions, 28 deletions
diff --git a/src/display/canvas-text.cpp b/src/display/canvas-text.cpp
index a563bddac..998b7054f 100644
--- a/src/display/canvas-text.cpp
+++ b/src/display/canvas-text.cpp
@@ -41,16 +41,16 @@ sp_canvastext_get_type (void)
static GType type = 0;
if (!type) {
- GTypeInfo info = {
+ GTypeInfo info = {
sizeof (SPCanvasTextClass),
- NULL, NULL,
+ NULL, NULL,
(GClassInitFunc) sp_canvastext_class_init,
- NULL, NULL,
+ NULL, NULL,
sizeof (SPCanvasText),
- 0,
+ 0,
(GInstanceInitFunc) sp_canvastext_init,
- NULL
- };
+ NULL
+ };
type = g_type_register_static (SP_TYPE_CANVAS_ITEM, "SPCanvasText", &info, (GTypeFlags)0);
}
return type;
@@ -115,28 +115,25 @@ sp_canvastext_render (SPCanvasItem *item, SPCanvasBuf *buf)
if (!buf->ct)
return;
- Geom::Point s = cl->s * cl->affine;
- double offsetx = s[Geom::X] - buf->rect.left();
- double offsety = s[Geom::Y] - buf->rect.top();
- offsetx -= cl->anchor_offset_x;
- offsety -= cl->anchor_offset_y;
-
cairo_set_font_size(buf->ct, cl->fontsize);
if (cl->background){
cairo_text_extents_t extents;
cairo_text_extents(buf->ct, cl->text, &extents);
- double border = cl->border;
- cairo_rectangle(buf->ct, offsetx - extents.x_bearing - border,
- offsety + extents.y_bearing - border,
- extents.width + 2*border,
- extents.height + 2*border);
+ cairo_rectangle(buf->ct, item->x1 - buf->rect.left(),
+ item->y1 - buf->rect.top(),
+ item->x2 - item->x1,
+ item->y2 - item->y1);
ink_cairo_set_source_rgba32(buf->ct, cl->rgba_background);
cairo_fill(buf->ct);
}
+ Geom::Point s = cl->s * cl->affine;
+ double offsetx = s[Geom::X] - cl->anchor_offset_x - buf->rect.left();
+ double offsety = s[Geom::Y] - cl->anchor_offset_y - buf->rect.top();
+
cairo_move_to(buf->ct, offsetx, offsety);
cairo_text_path(buf->ct, cl->text);
@@ -164,8 +161,10 @@ sp_canvastext_update (SPCanvasItem *item, Geom::Affine const &affine, unsigned i
cl->affine = affine;
Geom::Point s = cl->s * affine;
+ // Point s specifies the position of the anchor, which is at the bounding box of the text itself (i.e. not at the border of the filled background rectangle)
+ // The relative position of the anchor can be set using e.g. anchor_position = TEXT_ANCHOR_LEFT
- // set up a temporary cairo_t to measure the text extents; it would be better to compute this in the render()
+ // Set up a temporary cairo_t to measure the text extents; it would be better to compute this in the render()
// method but update() seems to be called before so we don't have the information available when we need it
cairo_surface_t *tmp_surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, 1, 1);
cairo_t* tmp_buf = cairo_create(tmp_surface);
@@ -175,28 +174,58 @@ sp_canvastext_update (SPCanvasItem *item, Geom::Affine const &affine, unsigned i
cairo_text_extents(tmp_buf, cl->text, &extents);
double border = cl->border;
- item->x1 = s[Geom::X] - extents.x_bearing - 2*border;
- item->y1 = s[Geom::Y] + extents.y_bearing - 2*border;
- item->x2 = s[Geom::X] + extents.width + 2*border;
- item->y2 = s[Geom::Y] + extents.height + 2*border;
+ item->x1 = s[Geom::X] + extents.x_bearing - border;
+ item->y1 = s[Geom::Y] + extents.y_bearing - border;
+ item->x2 = item->x1 + extents.width + 2*border;
+ item->y2 = item->y1 + extents.height + 2*border;
+
+ /* FROM: http://lists.cairographics.org/archives/cairo-bugs/2009-March/003014.html
+ - Glyph surfaces: In most font rendering systems, glyph surfaces
+ have an origin at (0,0) and a bounding box that is typically
+ represented as (x_bearing,y_bearing,width,height). Depending on
+ which way y progresses in the system, y_bearing may typically be
+ negative (for systems similar to cairo, with origin at top left),
+ or be positive (in systems like PDF with origin at bottom left).
+ No matter which is the case, it is important to note that
+ (x_bearing,y_bearing) is the coordinates of top-left of the glyph
+ relative to the glyph origin. That is, for example:
+
+ Scaled-glyph space:
+
+ (x_bearing,y_bearing) <-- negative numbers
+ +----------------+
+ | . |
+ | . |
+ |......(0,0) <---|-- glyph origin
+ | |
+ | |
+ +----------------+
+ (width+x_bearing,height+y_bearing)
+
+ Note the similarity of the origin to the device space. That is
+ exactly how we use the device_offset to represent scaled glyphs:
+ to use the device-space origin as the glyph origin.
+ */
// adjust update region according to anchor shift
+
+
switch (cl->anchor_position){
case TEXT_ANCHOR_LEFT:
- cl->anchor_offset_x = -2*border;
+ cl->anchor_offset_x = 0;
cl->anchor_offset_y = -extents.height/2;
break;
case TEXT_ANCHOR_RIGHT:
- cl->anchor_offset_x = extents.width + 2*border;
+ cl->anchor_offset_x = extents.width;
cl->anchor_offset_y = -extents.height/2;
break;
case TEXT_ANCHOR_BOTTOM:
cl->anchor_offset_x = extents.width/2;
- cl->anchor_offset_y = 2*border;
+ cl->anchor_offset_y = 0;
break;
case TEXT_ANCHOR_TOP:
cl->anchor_offset_x = extents.width/2;
- cl->anchor_offset_y = -extents.height - 2*border;
+ cl->anchor_offset_y = -extents.height;
break;
case TEXT_ANCHOR_ZERO:
cl->anchor_offset_x = 0;
@@ -209,6 +238,9 @@ sp_canvastext_update (SPCanvasItem *item, Geom::Affine const &affine, unsigned i
break;
}
+ cl->anchor_offset_x += extents.x_bearing;
+ cl->anchor_offset_y += extents.height + extents.y_bearing;
+
item->x1 -= cl->anchor_offset_x;
item->x2 -= cl->anchor_offset_x;
item->y1 -= cl->anchor_offset_y;
@@ -220,6 +252,8 @@ sp_canvastext_update (SPCanvasItem *item, Geom::Affine const &affine, unsigned i
SPCanvasItem *
sp_canvastext_new(SPCanvasGroup *parent, SPDesktop *desktop, Geom::Point pos, gchar const *new_text)
{
+ // Pos specifies the position of the anchor, which is at the bounding box of the text itself (i.e. not at the border of the filled background rectangle)
+ // The relative position of the anchor can be set using e.g. anchor_position = TEXT_ANCHOR_LEFT
SPCanvasItem *item = sp_canvas_item_new(parent, SP_TYPE_CANVASTEXT, NULL);
SPCanvasText *ct = SP_CANVASTEXT(item);
@@ -230,8 +264,6 @@ sp_canvastext_new(SPCanvasGroup *parent, SPDesktop *desktop, Geom::Point pos, gc
g_free(ct->text);
ct->text = g_strdup(new_text);
- // TODO: anything else to do?
-
return item;
}
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