[gtk+] gsk: Add gsk_rounded_rect_shrink()

[Benjamin Otte <otte src gnome org>]

commit a9809e5d30fbf4d5e3b555b5489d75102d5d30d0
Author: Benjamin Otte <otte redhat com>
Date:   Sun Dec 18 17:10:45 2016 +0100

    gsk: Add gsk_rounded_rect_shrink()
    
    ... and replace _gtk_rounded_box_grow() and _gtk_rounded_box_shrink()
    with it.

 docs/reference/gsk/gsk4-sections.txt |    1 +
 gsk/gskroundedrect.c                 |   72 ++++++++++++++++++++++++++++++++++
 gsk/gskroundedrect.h                 |    6 +++
 gtk/gtkcssshadowvalue.c              |    8 ++--
 gtk/gtkrender.c                      |    2 +-
 gtk/gtkrenderbackground.c            |    4 +-
 gtk/gtkrenderborder.c                |   10 ++--
 gtk/gtkroundedbox.c                  |   62 -----------------------------
 gtk/gtkroundedboxprivate.h           |   11 -----
 9 files changed, 91 insertions(+), 85 deletions(-)
---
diff --git a/docs/reference/gsk/gsk4-sections.txt b/docs/reference/gsk/gsk4-sections.txt
index f5cc151..3b47dab 100644
--- a/docs/reference/gsk/gsk4-sections.txt
+++ b/docs/reference/gsk/gsk4-sections.txt
@@ -72,5 +72,6 @@ gsk_rounded_rect_init_copy
 gsk_rounded_rect_init_from_rect
 gsk_rounded_rect_normalize
 gsk_rounded_rect_offset
+gsk_rounded_rect_shrink
 gsk_rounded_rect_is_rectilinear
 </SECTION>
diff --git a/gsk/gskroundedrect.c b/gsk/gskroundedrect.c
index 0e4173a..f1ecc2b 100644
--- a/gsk/gskroundedrect.c
+++ b/gsk/gskroundedrect.c
@@ -205,6 +205,78 @@ gsk_rounded_rect_offset (GskRoundedRect *self,
   return self;
 }
 
+static void
+border_radius_shrink (graphene_size_t *corner,
+                      double           width,
+                      double           height)
+{
+  if (corner->width > 0)
+    corner->width -= width;
+  if (corner->height > 0)
+    corner->height -= height;
+
+  if (corner->width <= 0 || corner->height <= 0)
+    {
+      corner->width = 0;
+      corner->height = 0;
+    }
+}
+
+/**
+ * gsk_rounded_rect_shrink:
+ * @self: The @GskRoundedRect to shrink or grow
+ * @top: How far to move the top side downwards
+ * @right: How far to move the right side to the left
+ * @bottom: How far to move the bottom side upwards
+ * @left: How far to move the left side to the right
+ *
+ * Shrinks (or grows) the given rectangle by moving the 4 sides
+ * according to the offsets given. The corner radii will be changed
+ * in a way that tries to keep the center of the corner circle intact.
+ * This emulates CSS behavior.
+ *
+ * This function also works for growing rectangles if you pass
+ * negative values for the @top, @right, @bottom or @left.
+ *
+ * Returns: @self
+ **/
+GskRoundedRect *
+gsk_rounded_rect_shrink (GskRoundedRect *self,
+                         float           top,
+                         float           right,
+                         float           bottom,
+                         float           left)
+{
+  if (self->bounds.size.width - left - right < 0)
+    {
+      self->bounds.origin.x += left * self->bounds.size.width / (left + right);
+      self->bounds.size.width = 0;
+    }
+  else
+    {
+      self->bounds.origin.x += left;
+      self->bounds.size.width -= left + right;
+    }
+
+  if (self->bounds.size.height - bottom - top < 0)
+    {
+      self->bounds.origin.y += top * self->bounds.size.height / (top + bottom);
+      self->bounds.size.height = 0;
+    }
+  else
+    {
+      self->bounds.origin.y += top;
+      self->bounds.size.height -= top + bottom;
+    }
+
+  border_radius_shrink (&self->corner[GSK_CORNER_TOP_LEFT], left, top);
+  border_radius_shrink (&self->corner[GSK_CORNER_TOP_RIGHT], right, top);
+  border_radius_shrink (&self->corner[GSK_CORNER_BOTTOM_RIGHT], right, bottom);
+  border_radius_shrink (&self->corner[GSK_CORNER_BOTTOM_LEFT], left, bottom);
+
+  return self;
+}
+
 /**
  * gsk_rounded_rect_is_rectilinear:
  * @self: the #GskRoundedRect to check
diff --git a/gsk/gskroundedrect.h b/gsk/gskroundedrect.h
index 96551ed..9a3d33e 100644
--- a/gsk/gskroundedrect.h
+++ b/gsk/gskroundedrect.h
@@ -87,6 +87,12 @@ GDK_AVAILABLE_IN_3_90
 GskRoundedRect *        gsk_rounded_rect_offset                 (GskRoundedRect           *self,
                                                                  float                     dx,
                                                                  float                     dy);
+GDK_AVAILABLE_IN_3_90
+GskRoundedRect *        gsk_rounded_rect_shrink                 (GskRoundedRect           *self,
+                                                                 float                     top,
+                                                                 float                     right,
+                                                                 float                     bottom,
+                                                                 float                     left);
 
 GDK_AVAILABLE_IN_3_90
 gboolean                gsk_rounded_rect_is_rectilinear         (GskRoundedRect           *self);
diff --git a/gtk/gtkcssshadowvalue.c b/gtk/gtkcssshadowvalue.c
index 24e852b..6edd51a 100644
--- a/gtk/gtkcssshadowvalue.c
+++ b/gtk/gtkcssshadowvalue.c
@@ -925,7 +925,7 @@ _gtk_css_shadow_value_paint_box (const GtkCssValue   *shadow,
       gsk_rounded_rect_path (padding_box, cr);
       outside = spread + clip_radius + MAX (fabs (x), fabs (y));
       clip_box = *padding_box;
-      _gtk_rounded_box_grow (&clip_box, outside, outside, outside, outside);
+      gsk_rounded_rect_shrink (&clip_box, -outside, -outside, -outside, -outside);
       _gtk_rounded_box_clip_path (&clip_box, cr);
 
       cairo_clip (cr);
@@ -935,12 +935,12 @@ _gtk_css_shadow_value_paint_box (const GtkCssValue   *shadow,
   gsk_rounded_rect_offset (&box, x, y);
 
   if (shadow->inset)
-    _gtk_rounded_box_shrink (&box, spread, spread, spread, spread);
+    gsk_rounded_rect_shrink (&box, spread, spread, spread, spread);
   else /* Outset */
-    _gtk_rounded_box_grow (&box, spread, spread, spread, spread);
+    gsk_rounded_rect_shrink (&box, -spread, -spread, -spread, -spread);
 
   clip_box = *padding_box;
-  _gtk_rounded_box_shrink (&clip_box, -clip_radius, -clip_radius, -clip_radius, -clip_radius);
+  gsk_rounded_rect_shrink (&clip_box, -clip_radius, -clip_radius, -clip_radius, -clip_radius);
 
   if (!needs_blur (shadow))
     draw_shadow (shadow, cr, &box, &clip_box, GTK_BLUR_NONE);
diff --git a/gtk/gtkrender.c b/gtk/gtkrender.c
index e23d712..a0c086b 100644
--- a/gtk/gtkrender.c
+++ b/gtk/gtkrender.c
@@ -986,7 +986,7 @@ gtk_render_content_path (GtkStyleContext *context,
   _gtk_rounded_box_init_rect (&box, x, y, width, height);
   _gtk_rounded_box_apply_border_radius_for_style (&box, gtk_style_context_lookup_style (context), 0);
 
-  _gtk_rounded_box_shrink (&box,
+  gsk_rounded_rect_shrink (&box,
                            _gtk_css_number_value_get (_gtk_style_context_peek_property (context, 
GTK_CSS_PROPERTY_BORDER_TOP_WIDTH), 100)
                            + _gtk_css_number_value_get (_gtk_style_context_peek_property (context, 
GTK_CSS_PROPERTY_PADDING_TOP), 100),
                            _gtk_css_number_value_get (_gtk_style_context_peek_property (context, 
GTK_CSS_PROPERTY_BORDER_RIGHT_WIDTH), 100)
diff --git a/gtk/gtkrenderbackground.c b/gtk/gtkrenderbackground.c
index 10f54c6..4beafb2 100644
--- a/gtk/gtkrenderbackground.c
+++ b/gtk/gtkrenderbackground.c
@@ -555,12 +555,12 @@ gtk_theming_background_init (GtkThemingBackground *bg,
   _gtk_rounded_box_apply_border_radius_for_style (&bg->boxes[GTK_CSS_AREA_BORDER_BOX], bg->style, junction);
 
   bg->boxes[GTK_CSS_AREA_PADDING_BOX] = bg->boxes[GTK_CSS_AREA_BORDER_BOX];
-  _gtk_rounded_box_shrink (&bg->boxes[GTK_CSS_AREA_PADDING_BOX],
+  gsk_rounded_rect_shrink (&bg->boxes[GTK_CSS_AREA_PADDING_BOX],
                           border.top, border.right,
                           border.bottom, border.left);
 
   bg->boxes[GTK_CSS_AREA_CONTENT_BOX] = bg->boxes[GTK_CSS_AREA_PADDING_BOX];
-  _gtk_rounded_box_shrink (&bg->boxes[GTK_CSS_AREA_CONTENT_BOX],
+  gsk_rounded_rect_shrink (&bg->boxes[GTK_CSS_AREA_CONTENT_BOX],
                           padding.top, padding.right,
                           padding.bottom, padding.left);
 }
diff --git a/gtk/gtkrenderborder.c b/gtk/gtkrenderborder.c
index 7c41861..9696c6c 100644
--- a/gtk/gtkrenderborder.c
+++ b/gtk/gtkrenderborder.c
@@ -362,7 +362,7 @@ render_frame_fill (cairo_t        *cr,
   guint i, j;
 
   padding_box = *border_box;
-  _gtk_rounded_box_shrink (&padding_box,
+  gsk_rounded_rect_shrink (&padding_box,
                            border_width[GTK_CSS_TOP],
                            border_width[GTK_CSS_RIGHT],
                            border_width[GTK_CSS_BOTTOM],
@@ -486,7 +486,7 @@ render_frame_stroke (cairo_t        *cr,
                       border_width[0] != border_width[3] ;
 
   stroke_box = *border_box;
-  _gtk_rounded_box_shrink (&stroke_box,
+  gsk_rounded_rect_shrink (&stroke_box,
                            border_width[GTK_CSS_TOP] / 2.0,
                            border_width[GTK_CSS_RIGHT] / 2.0,
                            border_width[GTK_CSS_BOTTOM] / 2.0,
@@ -513,7 +513,7 @@ render_frame_stroke (cairo_t        *cr,
       GskRoundedRect padding_box;
 
       padding_box = *border_box;
-      _gtk_rounded_box_shrink (&padding_box,
+      gsk_rounded_rect_shrink (&padding_box,
                                border_width[GTK_CSS_TOP],
                                border_width[GTK_CSS_RIGHT],
                                border_width[GTK_CSS_BOTTOM],
@@ -640,7 +640,7 @@ render_border (cairo_t        *cr,
             render_frame_fill (cr, border_box, other_border, colors, dont_draw);
             
             other_box = *border_box;
-            _gtk_rounded_box_shrink (&other_box,
+            gsk_rounded_rect_shrink (&other_box,
                                      2 * other_border[GTK_CSS_TOP],
                                      2 * other_border[GTK_CSS_RIGHT],
                                      2 * other_border[GTK_CSS_BOTTOM],
@@ -674,7 +674,7 @@ render_border (cairo_t        *cr,
             render_frame_fill (cr, border_box, other_border, colors, dont_draw);
             
             other_box = *border_box;
-            _gtk_rounded_box_shrink (&other_box,
+            gsk_rounded_rect_shrink (&other_box,
                                      other_border[GTK_CSS_TOP],
                                      other_border[GTK_CSS_RIGHT],
                                      other_border[GTK_CSS_BOTTOM],
diff --git a/gtk/gtkroundedbox.c b/gtk/gtkroundedbox.c
index 73b9746..5dafd63 100644
--- a/gtk/gtkroundedbox.c
+++ b/gtk/gtkroundedbox.c
@@ -151,68 +151,6 @@ _gtk_rounded_box_apply_outline_radius_for_style (GskRoundedRect   *box,
   _gtk_rounded_box_apply_border_radius (box, corner, junction);
 }
 
-static void
-gtk_css_border_radius_grow (graphene_size_t *corner,
-                            double           width,
-                            double           height)
-{
-  if (corner->width)
-    corner->width += width;
-  if (corner->height)
-    corner->height += height;
-
-  if (corner->width <= 0 || corner->height <= 0)
-    {
-      corner->width = 0;
-      corner->height = 0;
-    }
-}
-
-void
-_gtk_rounded_box_grow (GskRoundedRect *box,
-                       double          top,
-                       double          right,
-                       double          bottom,
-                       double          left)
-{
-  if (box->bounds.size.width + left + right < 0)
-    {
-      box->bounds.origin.x -= left * box->bounds.size.width / (left + right);
-      box->bounds.size.width = 0;
-    }
-  else
-    {
-      box->bounds.origin.x -= left;
-      box->bounds.size.width += left + right;
-    }
-
-  if (box->bounds.size.height + bottom + top < 0)
-    {
-      box->bounds.origin.y -= top * box->bounds.size.height / (top + bottom);
-      box->bounds.size.height = 0;
-    }
-  else
-    {
-      box->bounds.origin.y -= top;
-      box->bounds.size.height += top + bottom;
-    }
-
-  gtk_css_border_radius_grow (&box->corner[GSK_CORNER_TOP_LEFT], left, top);
-  gtk_css_border_radius_grow (&box->corner[GSK_CORNER_TOP_RIGHT], right, top);
-  gtk_css_border_radius_grow (&box->corner[GSK_CORNER_BOTTOM_RIGHT], right, bottom);
-  gtk_css_border_radius_grow (&box->corner[GSK_CORNER_BOTTOM_LEFT], left, bottom);
-}
-
-void
-_gtk_rounded_box_shrink (GskRoundedRect *box,
-                         double          top,
-                         double          right,
-                         double          bottom,
-                         double          left)
-{
-  _gtk_rounded_box_grow (box, -top, -right, -bottom, -left);
-}
-
 typedef struct {
   double angle1;
   double angle2;
diff --git a/gtk/gtkroundedboxprivate.h b/gtk/gtkroundedboxprivate.h
index 957bb3e..474c56c 100644
--- a/gtk/gtkroundedboxprivate.h
+++ b/gtk/gtkroundedboxprivate.h
@@ -42,17 +42,6 @@ void            _gtk_rounded_box_apply_outline_radius_for_style (GskRoundedRect
                                                                  GtkCssStyle            *style,
                                                                  GtkJunctionSides        junction);
 
-void            _gtk_rounded_box_grow                           (GskRoundedRect         *box,
-                                                                 double                  top,
-                                                                 double                  right,
-                                                                 double                  bottom,
-                                                                 double                  left);
-void            _gtk_rounded_box_shrink                         (GskRoundedRect         *box,
-                                                                 double                  top,
-                                                                 double                  right,
-                                                                 double                  bottom,
-                                                                 double                  left);
-
 double          _gtk_rounded_box_guess_length                   (const GskRoundedRect   *box,
                                                                  GtkCssSide              side);