Fix capsule edge case

5 files changed, 42 insertions, 9 deletions

diff --git a/comet.conf b/comet.conf
index bea53a2..3a2fd09 100644
--- a/comet.conf
+++ b/comet.conf
@@ -68,11 +68,11 @@
 
 [block.sl]
     type = slider
-    bar-value = 10
+    bar-value = 88
     color = #18baf2
     bar-width = 100
     bar-height = 10
-    bar-color = #afafaf
+    bar-color = #afafaf, #f1baee
     bar-line-color = #000
     bar-line-width = 2
     bar-bg-color = #fff
diff --git a/src/blocks/slider.c b/src/blocks/slider.c
index 3fe6e8c..8c89ddf 100644
--- a/src/blocks/slider.c
+++ b/src/blocks/slider.c
@@ -30,7 +30,7 @@ static void block_slider_render(layout_t *layout, cairo_t *cr)
 
     const int radius = slider->height / 2;
     int bar_y = layout->y + (layout->height - slider->height) / 2;
-    int bar_x = layout->x + layout->height / 2;
+    int bar_x = layout->x + (layout->width - slider->width) / 2;
 
     cairo_matrix_t matrix;
     cairo_matrix_init_scale(&matrix, 1.0 / slider->width, 1.0);
@@ -38,7 +38,7 @@ static void block_slider_render(layout_t *layout, cairo_t *cr)
 
     cairo_pattern_t *pattern = slider->bg_color.pattern;
     if (pattern != NULL) {
-        render_capsule(cr, bar_x, bar_y, slider->width, radius, slider->line_width);
+        render_capsule_fast(cr, bar_x, bar_y, slider->width, radius, radius);
 
         cairo_pattern_set_matrix(pattern, &matrix);
         cairo_set_source(cr, pattern);
@@ -48,7 +48,7 @@ static void block_slider_render(layout_t *layout, cairo_t *cr)
     pattern = slider->bar_color.pattern;
     if (pattern != NULL) {
         int current = slider->width * (slider->value / 100.0);
-        render_capsule(cr, bar_x, bar_y, current, radius, slider->line_width);
+        render_capsule(cr, bar_x, bar_y, current, radius, radius);
 
         cairo_pattern_set_matrix(pattern, &matrix);
         cairo_set_source(cr, pattern);
@@ -57,7 +57,8 @@ static void block_slider_render(layout_t *layout, cairo_t *cr)
 
     pattern = slider->line_color.pattern;
     if (pattern != NULL) {
-        render_capsule(cr, bar_x, bar_y, slider->width, radius, slider->line_width);
+        int line_radius = radius - slider->line_width / 2;
+        render_capsule_fast(cr, bar_x, bar_y, slider->width, radius, line_radius);
 
         cairo_pattern_set_matrix(pattern, &matrix);
         cairo_set_source(cr, pattern);
diff --git a/src/layout.c b/src/layout.c
index 193ebbd..bfc25c0 100644
--- a/src/layout.c
+++ b/src/layout.c
@@ -107,7 +107,7 @@ void layout_render(layout_t *layout, cairo_t *cr)
     // Render background
     cairo_pattern_t *pattern = layout->block->bg_color.pattern;
     if (pattern != NULL) {
-        render_capsule(cr, block_x, block_y, layout->width - layout->x_padding, radius, radius);
+        render_capsule_fast(cr, block_x, block_y, layout->width - layout->x_padding, radius, radius);
 
         cairo_pattern_set_matrix(pattern, &matrix);
         cairo_set_source(cr, pattern);
@@ -118,7 +118,7 @@ void layout_render(layout_t *layout, cairo_t *cr)
     pattern = layout->block->line_color.pattern;
     if (pattern != NULL) {
         int line_radius = radius - layout->line_width / 2;
-        render_capsule(cr, block_x, block_y, layout->width - layout->x_padding, radius, line_radius);
+        render_capsule_fast(cr, block_x, block_y, layout->width - layout->x_padding, radius, line_radius);
 
         cairo_pattern_set_matrix(pattern, &matrix);
         cairo_set_source(cr, pattern);
diff --git a/src/util.c b/src/util.c
index f9e00f2..b06fbae 100644
--- a/src/util.c
+++ b/src/util.c
@@ -214,9 +214,10 @@ bool iszero(const void *ptr, size_t size)
     return true;
 }
 
-void render_capsule(cairo_t *cr, int x, int y, int w, int r1, int r2)
+void render_capsule_fast(cairo_t *cr, int x, int y, int w, int r1, int r2)
 {
     const double degree = M_PI / 180.0;
+    assert(w >= r1 * 2);
 
     cairo_new_sub_path(cr);
     cairo_arc(cr, x + r1, y + r1, r2, 90 * degree, 270 * degree);
@@ -224,6 +225,33 @@ void render_capsule(cairo_t *cr, int x, int y, int w, int r1, int r2)
     cairo_close_path(cr);
 }
 
+void render_capsule(cairo_t *cr, int x, int y, int w, int r1, int r2)
+{
+    // Fast path
+    if (w >= r1 * 2) {
+        render_capsule_fast(cr, x, y, w, r1, r2);
+        return;
+    }
+
+    if (w == 0) return;
+
+    const double degree = M_PI / 180.0;
+    int x_off = -(r1 - w);
+
+    double angle1 = acos(1.0 - (w / 2.0) / (double)r1);
+    double angle2 = acos(1.0 - (w / 2.0) / (double)r1);
+
+    double left1  = 180 * degree - angle2,
+           left2  = 180 * degree + angle1,
+           right1 = 360 * degree - angle2,
+           right2 = angle2;
+
+    cairo_new_sub_path(cr);
+    cairo_arc(cr, x + r1, y + r1, r2, left1, left2);
+    cairo_arc(cr, x + x_off, y + r1, r2, right1, right2);
+    cairo_close_path(cr);
+}
+
 int snprintf_units(char *buffer, size_t max, uint64_t bytes, unit_t unit)
 {
     int base = unit & UNIT_SI ? 1000 : 1024;
diff --git a/src/util.h b/src/util.h
index e40a11a..76c87c0 100644
--- a/src/util.h
+++ b/src/util.h
@@ -85,6 +85,10 @@ void strfree(char **list);
 
 bool iszero(const void *ptr, size_t size);
 
+// Render a capsule shape. Cannot handle w < 2*r1
+void render_capsule_fast(cairo_t *cr, int x, int y, int w, int r1, int r2);
+
+// Render a capsule shape
 void render_capsule(cairo_t *cr, int x, int y, int w, int r1, int r2);
 
 typedef enum {