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Render error underlines as render nodes

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Use a sequence of transformed squares,
instead of a cairo node. The drawing is not
identical to the previous code, but reasonably
close.
This commit is contained in:
Matthias Clasen 2019-07-23 17:21:16 -04:00
parent fb06b7fa94
commit 3278e9ab6c
1 changed files with 49 additions and 81 deletions
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130
gtk/gskpango.c
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@ -187,78 +187,7 @@ gsk_pango_renderer_draw_trapezoid (PangoRenderer *renderer,
cairo_destroy (cr);
}
/* Draws an error underline that looks like one of:
* H E H
* /\ /\ /\ /\ /\ -
* A/ \ / \ / \ A/ \ / \ |
* \ \ / \ / /D \ \ / \ |
* \ \/ C \/ / \ \/ C \ | height = HEIGHT_SQUARES * square
* \ /\ F / \ F /\ \ |
* \ / \ / \ / \ \G |
* \ / \ / \ / \ / |
* \/ \/ \/ \/ -
* B B
* |---|
* unit_width = (HEIGHT_SQUARES - 1) * square
*
* The x, y, width, height passed in give the desired bounding box;
* x/width are adjusted to make the underline a integer number of units
* wide.
*/
#define HEIGHT_SQUARES 2.5
static void
draw_error_underline (cairo_t *cr,
double x,
double y,
double width,
double height)
{
double square = height / HEIGHT_SQUARES;
double unit_width = (HEIGHT_SQUARES - 1) * square;
double double_width = 2 * unit_width;
int width_units = (width + unit_width / 2) / unit_width;
double y_top, y_bottom;
double x_left, x_middle, x_right;
int i;
x += (width - width_units * unit_width) / 2;
y_top = y;
y_bottom = y + height;
/* Bottom of squiggle */
x_middle = x + unit_width;
x_right = x + double_width;
cairo_move_to (cr, x - square / 2, y_top + square / 2); /* A */
for (i = 0; i < width_units-2; i += 2)
{
cairo_line_to (cr, x_middle, y_bottom); /* B */
cairo_line_to (cr, x_right, y_top + square); /* C */
x_middle += double_width;
x_right += double_width;
}
cairo_line_to (cr, x_middle, y_bottom); /* B */
if (i + 1 == width_units)
cairo_line_to (cr, x_middle + square / 2, y_bottom - square / 2); /* G */
else if (i + 2 == width_units) {
cairo_line_to (cr, x_right + square / 2, y_top + square / 2); /* D */
cairo_line_to (cr, x_right, y_top); /* E */
}
/* Top of squiggle */
x_left = x_middle - unit_width;
for (; i >= 0; i -= 2)
{
cairo_line_to (cr, x_middle, y_bottom - square); /* F */
cairo_line_to (cr, x_left, y_top); /* H */
x_left -= double_width;
x_middle -= double_width;
}
}
#define HEIGHT_RATIO (M_SQRT2/5.0)
static void
gsk_pango_renderer_draw_error_underline (PangoRenderer *renderer,
@ -267,22 +196,61 @@ gsk_pango_renderer_draw_error_underline (PangoRenderer *renderer,
int width,
int height)
{
GdkRGBA rgba;
double xx, yy, ww, hh;
double hs;
double e, o;
GskPangoRenderer *crenderer = (GskPangoRenderer *) (renderer);
cairo_t *cr;
cr = gtk_snapshot_append_cairo (crenderer->snapshot, &crenderer->bounds);
xx = (double)x / PANGO_SCALE;
yy = (double)y / PANGO_SCALE;
ww = (double)width / PANGO_SCALE;
hh = (double)height / PANGO_SCALE;
hs = hh / M_SQRT2;
set_color (crenderer, PANGO_RENDER_PART_UNDERLINE, cr);
e = fmod (ww - 2 * hs * HEIGHT_RATIO, hs * (1 - HEIGHT_RATIO));
cairo_new_path (cr);
#if 0
gdk_rgba_parse (&rgba, "yellow");
gtk_snapshot_append_color (crenderer->snapshot, &rgba,
&GRAPHENE_RECT_INIT (xx, yy, ww, hh));
#endif
draw_error_underline (cr,
(double)x / PANGO_SCALE, (double)y / PANGO_SCALE,
(double)width / PANGO_SCALE, (double)height / PANGO_SCALE);
cairo_fill (cr);
get_color (crenderer, PANGO_RENDER_PART_UNDERLINE, &rgba);
gtk_snapshot_save (crenderer->snapshot);
gtk_snapshot_translate (crenderer->snapshot,
&GRAPHENE_POINT_INIT (xx, yy));
cairo_destroy (cr);
gtk_snapshot_rotate (crenderer->snapshot, 45);
gtk_snapshot_translate (crenderer->snapshot,
&GRAPHENE_POINT_INIT (e / 2 + hs * HEIGHT_RATIO,
- hs * HEIGHT_RATIO));
xx = yy = o = 0;
while (1)
{
if (o + hs * (1 + HEIGHT_RATIO) >= ww)
break;
gtk_snapshot_append_color (crenderer->snapshot, &rgba,
&GRAPHENE_RECT_INIT (xx, yy, hh, hh * HEIGHT_RATIO));
xx += hh * (1 - HEIGHT_RATIO);
yy -= hh * (1 - HEIGHT_RATIO);
o += hs * (1 - HEIGHT_RATIO);
if (o + hs * (1 + HEIGHT_RATIO) >= ww)
break;
gtk_snapshot_append_color (crenderer->snapshot, &rgba,
&GRAPHENE_RECT_INIT (xx, yy, hh * HEIGHT_RATIO, hh));
o += hs * (1 - HEIGHT_RATIO);
}
gtk_snapshot_restore (crenderer->snapshot);
}
static void