Added hairline support to cairo

1 files changed, 61 insertions, 0 deletions

diff --git a/src/cairo.c b/src/cairo.c
index b2bda657d..d141b56d2 100644
--- a/src/cairo.c
+++ b/src/cairo.c
@@ -1185,6 +1185,47 @@ cairo_set_line_width (cairo_t *cr, double width)
 slim_hidden_def (cairo_set_line_width);
 
 /**
+ * cairo_set_hairline:
+ * @cr: a #cairo_t
+ * @set_hairline: whether or not to set hairline mode
+ *
+ * Sets lines within the cairo context to be hairlines.
+ * Hairlines are logically zero-width lines that are drawn at the
+ * thinnest renderable width possible in the current context.
+ *
+ * On surfaces with native hairline support, the native hairline
+ * functionality will be used. Surfaces that support hairlines include:
+ * - pdf/ps: Encoded as 0-width line.
+ * - win32_printing: Rendered with PS_COSMETIC pen.
+ * - svg: Encoded as 1px non-scaling-stroke.
+ * - script: Encoded with set-hairline function.
+ *
+ * Cairo will always render hairlines at 1 device unit wide, even if
+ * an anisotropic scaling was applied to the stroke width. In the wild,
+ * handling of this situation is not well-defined. Some PDF, PS, and SVG
+ * renderers match Cairo's output, but some very popular implementations
+ * (Acrobat, Chrome, rsvg) will scale the hairline unevenly.
+ * As such, best practice is to reset any anisotropic scaling before calling
+ * cairo_stroke(). See https://cairographics.org/cookbook/ellipses/
+ * for an example.
+ *
+ * Since: 1.18
+ **/
+void
+cairo_set_hairline (cairo_t *cr, cairo_bool_t set_hairline)
+{
+    cairo_status_t status;
+
+    if (unlikely (cr->status))
+	return;
+
+    status = cr->backend->set_hairline (cr, set_hairline);
+    if (unlikely (status))
+	_cairo_set_error (cr, status);
+}
+slim_hidden_def (cairo_set_hairline);
+
+/**
  * cairo_set_line_cap:
  * @cr: a cairo context
  * @line_cap: a line cap style
@@ -4058,6 +4099,26 @@ cairo_get_line_width (cairo_t *cr)
 slim_hidden_def (cairo_get_line_width);
 
 /**
+ * cairo_get_hairline:
+ * @cr: a cairo context
+ *
+ * Returns whether or not hairline mode is set, as set by cairo_set_hairline().
+ *
+ * Return value: whether hairline mode is set.
+ *
+ * Since: 1.18
+ **/
+cairo_bool_t
+cairo_get_hairline (cairo_t *cr)
+{
+    if (unlikely (cr->status))
+        return FALSE;
+
+    return cr->backend->get_hairline (cr);
+}
+slim_hidden_def (cairo_get_hairline);
+
+/**
  * cairo_get_line_cap:
  * @cr: a cairo context
  *