[gnome-builder] line-changes: add support for rendering deleted lines

[Christian Hergert <chergert src gnome org>]

commit dcf67852001be8ec49354efa7d68dad62706a6c9
Author: Christian Hergert <chergert redhat com>
Date:   Tue Feb 16 19:08:51 2016 -0800

    line-changes: add support for rendering deleted lines
    
    This adds the IdeLineChangeGutterRenderer:show-line-deletions property.
    If set, it will renderer a small red triangle near the line deletion.
    It relies on the accuracy of line change tracking in the change monitors.
    These are not necessarily perfect today, but this should help us find and
    track down any errors with those.

 libide/ide-line-change-gutter-renderer.c |  182 +++++++++++++++++++++++++++++-
 1 files changed, 180 insertions(+), 2 deletions(-)
---
diff --git a/libide/ide-line-change-gutter-renderer.c b/libide/ide-line-change-gutter-renderer.c
index 24d2f03..28a845e 100644
--- a/libide/ide-line-change-gutter-renderer.c
+++ b/libide/ide-line-change-gutter-renderer.c
@@ -22,6 +22,13 @@
 #include "ide-line-change-gutter-renderer.h"
 #include "ide-vcs.h"
 
+#define DELETE_WIDTH   5.0
+#define DELETE_HEIGHT 10.0
+
+#if 0
+# define ARROW_TOWARDS_GUTTER
+#endif
+
 struct _IdeLineChangeGutterRenderer
 {
   GtkSourceGutterRenderer parent_instance;
@@ -34,9 +41,13 @@ struct _IdeLineChangeGutterRenderer
 
   GdkRGBA                 rgba_added;
   GdkRGBA                 rgba_changed;
+  GdkRGBA                 rgba_removed;
+
+  guint                   show_line_deletions : 1;
 
   guint                   rgba_added_set : 1;
   guint                   rgba_changed_set : 1;
+  guint                   rgba_removed_set : 1;
 };
 
 
@@ -46,12 +57,22 @@ G_DEFINE_TYPE (IdeLineChangeGutterRenderer,
 
 static GdkRGBA rgbaAdded;
 static GdkRGBA rgbaChanged;
+static GdkRGBA rgbaRemoved;
+
+enum {
+  PROP_0,
+  PROP_SHOW_LINE_DELETIONS,
+  LAST_PROP
+};
+
+static GParamSpec *properties [LAST_PROP];
 
 static void
 disconnect_style_scheme (IdeLineChangeGutterRenderer *self)
 {
   self->rgba_added_set = 0;
   self->rgba_changed_set = 0;
+  self->rgba_removed_set = 0;
 }
 
 static void
@@ -130,6 +151,22 @@ connect_style_scheme (IdeLineChangeGutterRenderer *self)
           if (foreground_set)
             self->rgba_changed_set = gdk_rgba_parse (&self->rgba_changed, foreground);
         }
+
+      style = gtk_source_style_scheme_get_style (style_scheme, "gutter:removed-line");
+
+      if (style)
+        {
+          g_autofree gchar *foreground = NULL;
+          gboolean foreground_set = 0;
+
+          g_object_get (style,
+                        "foreground-set", &foreground_set,
+                        "foreground", &foreground,
+                        NULL);
+
+          if (foreground_set)
+            self->rgba_removed_set = gdk_rgba_parse (&self->rgba_removed, foreground);
+        }
     }
 }
 
@@ -207,6 +244,8 @@ ide_line_change_gutter_renderer_draw (GtkSourceGutterRenderer      *renderer,
   GtkTextBuffer *buffer;
   GdkRGBA *rgba = NULL;
   IdeBufferLineFlags flags;
+  IdeBufferLineFlags prev_flags = 0;
+  IdeBufferLineFlags next_flags;
   guint lineno;
 
   g_return_if_fail (IDE_IS_LINE_CHANGE_GUTTER_RENDERER (self));
@@ -216,8 +255,7 @@ ide_line_change_gutter_renderer_draw (GtkSourceGutterRenderer      *renderer,
   g_return_if_fail (begin);
   g_return_if_fail (end);
 
-  GTK_SOURCE_GUTTER_RENDERER_CLASS (ide_line_change_gutter_renderer_parent_class)->
-    draw (renderer, cr, bg_area, cell_area, begin, end, state);
+  GTK_SOURCE_GUTTER_RENDERER_CLASS (ide_line_change_gutter_renderer_parent_class)->draw (renderer, cr, 
bg_area, cell_area, begin, end, state);
 
   buffer = gtk_text_iter_get_buffer (begin);
 
@@ -225,7 +263,11 @@ ide_line_change_gutter_renderer_draw (GtkSourceGutterRenderer      *renderer,
     return;
 
   lineno = gtk_text_iter_get_line (begin);
+
   flags = ide_buffer_get_line_flags (IDE_BUFFER (buffer), lineno);
+  next_flags = ide_buffer_get_line_flags (IDE_BUFFER (buffer), lineno + 1);
+  if (lineno > 0)
+    prev_flags = ide_buffer_get_line_flags (IDE_BUFFER (buffer), lineno - 1);
 
   if ((flags & IDE_BUFFER_LINE_FLAGS_ADDED) != 0)
     rgba = self->rgba_added_set ? &self->rgba_added : &rgbaAdded;
@@ -239,6 +281,91 @@ ide_line_change_gutter_renderer_draw (GtkSourceGutterRenderer      *renderer,
       gdk_cairo_set_source_rgba (cr, rgba);
       cairo_fill (cr);
     }
+
+  if (!self->show_line_deletions)
+    return;
+
+  /*
+   * If the next line is a deletion, but we were not a deletion, then
+   * draw our half the deletion mark.
+   */
+  if (((next_flags & IDE_BUFFER_LINE_FLAGS_DELETED) != 0) &&
+      ((flags & IDE_BUFFER_LINE_FLAGS_DELETED) == 0))
+    {
+      rgba = self->rgba_removed_set ? &self->rgba_removed : &rgbaRemoved;
+      gdk_cairo_set_source_rgba (cr, rgba);
+
+#ifdef ARROW_TOWARDS_GUTTER
+      cairo_move_to (cr,
+                     cell_area->x + cell_area->width,
+                     cell_area->y + cell_area->height);
+      cairo_line_to (cr,
+                     cell_area->x + cell_area->width - DELETE_WIDTH,
+                     cell_area->y + cell_area->height);
+      cairo_line_to (cr,
+                     cell_area->x + cell_area->width,
+                     cell_area->y + cell_area->height - (DELETE_HEIGHT / 2));
+      cairo_line_to (cr,
+                     cell_area->x + cell_area->width,
+                     cell_area->y + cell_area->height);
+#else
+      cairo_move_to (cr,
+                     cell_area->x + cell_area->width,
+                     cell_area->y + cell_area->height);
+      cairo_line_to (cr,
+                     cell_area->x + cell_area->width - DELETE_WIDTH,
+                     cell_area->y + cell_area->height);
+      cairo_line_to (cr,
+                     cell_area->x + cell_area->width - DELETE_WIDTH,
+                     cell_area->y + cell_area->height - (DELETE_HEIGHT / 2));
+      cairo_line_to (cr,
+                     cell_area->x + cell_area->width,
+                     cell_area->y + cell_area->height);
+#endif
+
+      cairo_fill (cr);
+    }
+
+  /*
+   * If the previous line was not a deletion, and we have a deletion, then
+   * draw our half the deletion mark.
+   */
+  if (((prev_flags & IDE_BUFFER_LINE_FLAGS_DELETED) == 0) &&
+      ((flags & IDE_BUFFER_LINE_FLAGS_DELETED) != 0))
+    {
+      rgba = self->rgba_removed_set ? &self->rgba_removed : &rgbaRemoved;
+      gdk_cairo_set_source_rgba (cr, rgba);
+
+#ifdef ARROW_TOWARDS_GUTTER
+      cairo_move_to (cr,
+                     cell_area->x + cell_area->width,
+                     cell_area->y);
+      cairo_line_to (cr,
+                     cell_area->x + cell_area->width,
+                     cell_area->y + (DELETE_HEIGHT / 2));
+      cairo_line_to (cr,
+                     cell_area->x + cell_area->width - DELETE_WIDTH,
+                     cell_area->y);
+      cairo_line_to (cr,
+                     cell_area->x + cell_area->width,
+                     cell_area->y);
+#else
+      cairo_move_to (cr,
+                     cell_area->x + cell_area->width,
+                     cell_area->y);
+      cairo_line_to (cr,
+                     cell_area->x + cell_area->width - DELETE_WIDTH,
+                     cell_area->y);
+      cairo_line_to (cr,
+                     cell_area->x + cell_area->width - DELETE_WIDTH,
+                     cell_area->y + (DELETE_HEIGHT / 2));
+      cairo_line_to (cr,
+                     cell_area->x + cell_area->width,
+                     cell_area->y);
+#endif
+
+      cairo_fill (cr);
+    }
 }
 
 static void
@@ -250,17 +377,68 @@ ide_line_change_gutter_renderer_dispose (GObject *object)
 }
 
 static void
+ide_line_change_gutter_renderer_get_property (GObject    *object,
+                                              guint       prop_id,
+                                              GValue     *value,
+                                              GParamSpec *pspec)
+{
+  IdeLineChangeGutterRenderer *self = IDE_LINE_CHANGE_GUTTER_RENDERER(object);
+
+  switch (prop_id)
+    {
+    case PROP_SHOW_LINE_DELETIONS:
+      g_value_set_boolean (value, self->show_line_deletions);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
+    }
+}
+
+static void
+ide_line_change_gutter_renderer_set_property (GObject      *object,
+                                              guint         prop_id,
+                                              const GValue *value,
+                                              GParamSpec   *pspec)
+{
+  IdeLineChangeGutterRenderer *self = IDE_LINE_CHANGE_GUTTER_RENDERER(object);
+
+  switch (prop_id)
+    {
+    case PROP_SHOW_LINE_DELETIONS:
+      self->show_line_deletions = g_value_get_boolean (value);
+      gtk_source_gutter_renderer_queue_draw (GTK_SOURCE_GUTTER_RENDERER (self));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
+    }
+}
+
+static void
 ide_line_change_gutter_renderer_class_init (IdeLineChangeGutterRendererClass *klass)
 {
   GtkSourceGutterRendererClass *renderer_class = GTK_SOURCE_GUTTER_RENDERER_CLASS (klass);
   GObjectClass *object_class = G_OBJECT_CLASS (klass);
 
   object_class->dispose = ide_line_change_gutter_renderer_dispose;
+  object_class->get_property = ide_line_change_gutter_renderer_get_property;
+  object_class->set_property = ide_line_change_gutter_renderer_set_property;
 
   renderer_class->draw = ide_line_change_gutter_renderer_draw;
 
+  properties [PROP_SHOW_LINE_DELETIONS] =
+    g_param_spec_boolean ("show-line-deletions",
+                          "Show Line Deletions",
+                          "If the deletion mark should be shown for deleted lines",
+                          FALSE,
+                          (G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+
+  g_object_class_install_properties (object_class, LAST_PROP, properties);
+
   gdk_rgba_parse (&rgbaAdded, "#8ae234");
   gdk_rgba_parse (&rgbaChanged, "#fcaf3e");
+  gdk_rgba_parse (&rgbaRemoved, "#ff0000");
 }
 
 static void