cairo-util: fix shadows for small clients

If the client is small (< 128 pixels in any ward),
then the shadows overlap and create dark lines behind clients.
This is a problem mosly with pop-up menues. The lines become observable
when the menu has less than three items. The other case is when
the client doesn't restrict its size when resizing (try
'weston-eventdemo --max-width=1 --max-height=1' for example)

This fixes a part of the bug:
https://bugs.freedesktop.org/show_bug.cgi?id=78511

v2:
  - rework computing of the size of corners
  - rewrite some comments
  - rename tile_mask to render_shadow (in separate patch)

Signed-off-by: Marek Chalupa <mchqwerty@gmail.com>
Tested-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
dev
Marek Chalupa 10 years ago committed by Pekka Paalanen
parent 0d7fe8d925
commit eaea470510
  1. 129
      shared/cairo-util.c

@ -142,7 +142,7 @@ render_shadow(cairo_t *cr, cairo_surface_t *surface,
{
cairo_pattern_t *pattern;
cairo_matrix_t matrix;
int i, fx, fy, vmargin;
int i, fx, fy, shadow_height, shadow_width;
cairo_set_source_rgba(cr, 0, 0, 0, 0.45);
cairo_set_operator(cr, CAIRO_OPERATOR_OVER);
@ -150,6 +150,14 @@ render_shadow(cairo_t *cr, cairo_surface_t *surface,
cairo_pattern_set_filter(pattern, CAIRO_FILTER_NEAREST);
for (i = 0; i < 4; i++) {
/* when fy is set, then we are working with lower corners,
* when fx is set, then we are working with right corners
*
* 00 ------- 01
* | |
* | |
* 10 ------- 11
*/
fx = i & 1;
fy = i >> 1;
@ -158,63 +166,92 @@ render_shadow(cairo_t *cr, cairo_surface_t *surface,
-y + fy * (128 - height));
cairo_pattern_set_matrix(pattern, &matrix);
if (fy)
vmargin = margin;
else
vmargin = top_margin;
shadow_width = margin;
shadow_height = fy ? margin : top_margin;
/* if the shadows together are greater than the surface, we need
* to fix it - set the shadow size to the half of
* the size of surface. Also handle the case when the size is
* not divisible by 2. In that case we need one part of the
* shadow to be one pixel greater. !fy or !fx, respectively,
* will do the work.
*/
if (height < 2 * shadow_height)
shadow_height = (height + !fy) / 2;
if (width < 2 * shadow_width)
shadow_width = (width + !fx) / 2;
cairo_reset_clip(cr);
cairo_rectangle(cr,
x + fx * (width - margin),
y + fy * (height - vmargin),
margin, vmargin);
x + fx * (width - shadow_width),
y + fy * (height - shadow_height),
shadow_width, shadow_height);
cairo_clip (cr);
cairo_mask(cr, pattern);
}
/* Top stretch */
cairo_matrix_init_translate(&matrix, 60, 0);
cairo_matrix_scale(&matrix, 8.0 / width, 1);
cairo_matrix_translate(&matrix, -x - width / 2, -y);
cairo_pattern_set_matrix(pattern, &matrix);
cairo_rectangle(cr, x + margin, y, width - 2 * margin, margin);
cairo_reset_clip(cr);
cairo_rectangle(cr,
x + margin,
y,
width - 2 * margin, margin);
cairo_clip (cr);
cairo_mask(cr, pattern);
shadow_width = width - 2 * margin;
shadow_height = top_margin;
if (height < 2 * shadow_height)
shadow_height = height / 2;
/* Bottom stretch */
cairo_matrix_translate(&matrix, 0, -height + 128);
cairo_pattern_set_matrix(pattern, &matrix);
if (shadow_width > 0 && shadow_height) {
/* Top stretch */
cairo_matrix_init_translate(&matrix, 60, 0);
cairo_matrix_scale(&matrix, 8.0 / width, 1);
cairo_matrix_translate(&matrix, -x - width / 2, -y);
cairo_pattern_set_matrix(pattern, &matrix);
cairo_rectangle(cr, x + margin, y, shadow_width, shadow_height);
cairo_reset_clip(cr);
cairo_rectangle(cr, x + margin, y + height - margin,
width - 2 * margin, margin);
cairo_clip (cr);
cairo_mask(cr, pattern);
cairo_reset_clip(cr);
cairo_rectangle(cr,
x + margin, y,
shadow_width, shadow_height);
cairo_clip (cr);
cairo_mask(cr, pattern);
/* Left stretch */
cairo_matrix_init_translate(&matrix, 0, 60);
cairo_matrix_scale(&matrix, 1, 8.0 / height);
cairo_matrix_translate(&matrix, -x, -y - height / 2);
cairo_pattern_set_matrix(pattern, &matrix);
cairo_reset_clip(cr);
cairo_rectangle(cr, x, y + margin, margin, height - 2 * margin);
cairo_clip (cr);
cairo_mask(cr, pattern);
/* Bottom stretch */
cairo_matrix_translate(&matrix, 0, -height + 128);
cairo_pattern_set_matrix(pattern, &matrix);
/* Right stretch */
cairo_matrix_translate(&matrix, -width + 128, 0);
cairo_pattern_set_matrix(pattern, &matrix);
cairo_rectangle(cr, x + width - margin, y + margin,
margin, height - 2 * margin);
cairo_reset_clip(cr);
cairo_clip (cr);
cairo_mask(cr, pattern);
cairo_reset_clip(cr);
cairo_rectangle(cr, x + margin, y + height - margin,
shadow_width, margin);
cairo_clip (cr);
cairo_mask(cr, pattern);
}
shadow_width = margin;
if (width < 2 * shadow_width)
shadow_width = width / 2;
shadow_height = height - margin - top_margin;
/* if height is smaller than sum of margins,
* then the shadow is already done by the corners */
if (shadow_height > 0 && shadow_width) {
/* Left stretch */
cairo_matrix_init_translate(&matrix, 0, 60);
cairo_matrix_scale(&matrix, 1, 8.0 / height);
cairo_matrix_translate(&matrix, -x, -y - height / 2);
cairo_pattern_set_matrix(pattern, &matrix);
cairo_reset_clip(cr);
cairo_rectangle(cr, x, y + top_margin,
shadow_width, shadow_height);
cairo_clip (cr);
cairo_mask(cr, pattern);
/* Right stretch */
cairo_matrix_translate(&matrix, -width + 128, 0);
cairo_pattern_set_matrix(pattern, &matrix);
cairo_rectangle(cr, x + width - shadow_width, y + top_margin,
shadow_width, shadow_height);
cairo_reset_clip(cr);
cairo_clip (cr);
cairo_mask(cr, pattern);
}
cairo_pattern_destroy(pattern);
cairo_reset_clip(cr);

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