[gimp/gimp-2-10] app: in perspective-clone tool, fix cursor presicion; hide brush while adjusting

[Ell <ell src gnome org>]

commit 5e6378a7a3fb4575efacd3a16a0b165de133296a
Author: Ell <ell_se yahoo com>
Date:   Thu Jan 31 06:18:17 2019 -0500

    app: in perspective-clone tool, fix cursor presicion; hide brush while adjusting
    
    In GimpPerspectiveCloneTool, use PIXEL_CENTER cursor precision
    while setting the source, and place the source-position handle at
    the center of the selected pixel, rather than at its top-left
    corner.
    
    Additionally, disable the paint tool while adjusting the
    perspective, so that the brush outline isn't shown, and the cursor
    precision remains SUBPIXEL, even if the hard-edge option is
    toggled.
    
    (cherry picked from commit e5c9314a88aa20331027537b350a8c4f37a35da4)

 app/tools/gimpperspectiveclonetool.c | 69 +++++++++++++++++++++++++++++++++---
 app/tools/gimpperspectiveclonetool.h | 24 +++++++------
 2 files changed, 77 insertions(+), 16 deletions(-)
---
diff --git a/app/tools/gimpperspectiveclonetool.c b/app/tools/gimpperspectiveclonetool.c
index f99223e7db..f05f010ec2 100644
--- a/app/tools/gimpperspectiveclonetool.c
+++ b/app/tools/gimpperspectiveclonetool.c
@@ -62,6 +62,8 @@ enum
 };
 
 
+static void     gimp_perspective_clone_tool_constructed    (GObject          *object);
+
 static gboolean gimp_perspective_clone_tool_initialize     (GimpTool         *tool,
                                                             GimpDisplay      *display,
                                                             GError          **error);
@@ -91,6 +93,11 @@ static void     gimp_perspective_clone_tool_motion         (GimpTool         *to
                                                             guint32           time,
                                                             GdkModifierType   state,
                                                             GimpDisplay      *display);
+static void     gimp_perspective_clone_tool_modifier_key   (GimpTool         *tool,
+                                                            GdkModifierType   key,
+                                                            gboolean          press,
+                                                            GdkModifierType   state,
+                                                            GimpDisplay      *display);
 static void     gimp_perspective_clone_tool_cursor_update  (GimpTool         *tool,
                                                             const GimpCoords *coords,
                                                             GdkModifierType   state,
@@ -151,9 +158,12 @@ gimp_perspective_clone_tool_register (GimpToolRegisterCallback  callback,
 static void
 gimp_perspective_clone_tool_class_init (GimpPerspectiveCloneToolClass *klass)
 {
+  GObjectClass      *object_class    = G_OBJECT_CLASS (klass);
   GimpToolClass     *tool_class      = GIMP_TOOL_CLASS (klass);
   GimpDrawToolClass *draw_tool_class = GIMP_DRAW_TOOL_CLASS (klass);
 
+  object_class->constructed  = gimp_perspective_clone_tool_constructed;
+
   tool_class->initialize     = gimp_perspective_clone_tool_initialize;
   tool_class->has_display    = gimp_perspective_clone_tool_has_display;
   tool_class->has_image      = gimp_perspective_clone_tool_has_image;
@@ -161,6 +171,7 @@ gimp_perspective_clone_tool_class_init (GimpPerspectiveCloneToolClass *klass)
   tool_class->button_press   = gimp_perspective_clone_tool_button_press;
   tool_class->button_release = gimp_perspective_clone_tool_button_release;
   tool_class->motion         = gimp_perspective_clone_tool_motion;
+  tool_class->modifier_key   = gimp_perspective_clone_tool_modifier_key;
   tool_class->cursor_update  = gimp_perspective_clone_tool_cursor_update;
   tool_class->oper_update    = gimp_perspective_clone_tool_oper_update;
   tool_class->options_notify = gimp_perspective_clone_tool_options_notify;
@@ -179,6 +190,19 @@ gimp_perspective_clone_tool_init (GimpPerspectiveCloneTool *clone_tool)
   gimp_matrix3_identity (&clone_tool->transform);
 }
 
+static void
+gimp_perspective_clone_tool_constructed (GObject *object)
+{
+  GimpPerspectiveCloneOptions *options;
+
+  options = GIMP_PERSPECTIVE_CLONE_TOOL_GET_OPTIONS (object);
+
+  G_OBJECT_CLASS (parent_class)->constructed (object);
+
+  if (options->clone_mode == GIMP_PERSPECTIVE_CLONE_MODE_ADJUST)
+    gimp_paint_tool_set_active (GIMP_PAINT_TOOL (object), FALSE);
+}
+
 static gboolean
 gimp_perspective_clone_tool_initialize (GimpTool     *tool,
                                         GimpDisplay  *display,
@@ -447,6 +471,39 @@ gimp_perspective_clone_tool_motion (GimpTool         *tool,
     }
 }
 
+static void
+gimp_perspective_clone_tool_modifier_key (GimpTool        *tool,
+                                          GdkModifierType  key,
+                                          gboolean         press,
+                                          GdkModifierType  state,
+                                          GimpDisplay     *display)
+{
+  GimpPerspectiveCloneTool    *clone_tool = GIMP_PERSPECTIVE_CLONE_TOOL (tool);
+  GimpPerspectiveCloneOptions *options;
+
+  options = GIMP_PERSPECTIVE_CLONE_TOOL_GET_OPTIONS (tool);
+
+  if (options->clone_mode == GIMP_PERSPECTIVE_CLONE_MODE_PAINT &&
+      key == gimp_get_toggle_behavior_mask ())
+    {
+      if (press)
+        {
+          clone_tool->saved_precision =
+            gimp_tool_control_get_precision (tool->control);
+          gimp_tool_control_set_precision (tool->control,
+                                           GIMP_CURSOR_PRECISION_PIXEL_CENTER);
+        }
+      else
+        {
+          gimp_tool_control_set_precision (tool->control,
+                                           clone_tool->saved_precision);
+        }
+    }
+
+  GIMP_TOOL_CLASS (parent_class)->modifier_key (tool, key, press, state,
+                                                display);
+}
+
 static void
 gimp_perspective_clone_tool_cursor_update (GimpTool         *tool,
                                            const GimpCoords *coords,
@@ -592,6 +649,7 @@ gimp_perspective_clone_tool_options_notify (GimpTool         *tool,
                                             const GParamSpec *pspec)
 {
   GimpPerspectiveCloneTool    *clone_tool = GIMP_PERSPECTIVE_CLONE_TOOL (tool);
+  GimpPaintTool               *paint_tool = GIMP_PAINT_TOOL (tool);
   GimpPerspectiveCloneOptions *clone_options;
 
   clone_options = GIMP_PERSPECTIVE_CLONE_OPTIONS (options);
@@ -608,13 +666,14 @@ gimp_perspective_clone_tool_options_notify (GimpTool         *tool,
 
       if (clone_options->clone_mode == GIMP_PERSPECTIVE_CLONE_MODE_PAINT)
         {
-          /* GimpPaintTool's notify callback will set the right precision */
-          g_object_notify (G_OBJECT (options), "hard");
-
           gimp_perspective_clone_set_transform (clone, &clone_tool->transform);
+
+          gimp_paint_tool_set_active (paint_tool, TRUE);
         }
       else
         {
+          gimp_paint_tool_set_active (paint_tool, FALSE);
+
           gimp_tool_control_set_precision (tool->control,
                                            GIMP_CURSOR_PRECISION_SUBPIXEL);
 
@@ -692,8 +751,8 @@ gimp_perspective_clone_tool_draw (GimpDrawTool *draw_tool)
 
       gimp_draw_tool_add_handle (draw_tool,
                                  GIMP_HANDLE_CROSS,
-                                 clone_tool->src_x,
-                                 clone_tool->src_y,
+                                 clone_tool->src_x + 0.5,
+                                 clone_tool->src_y + 0.5,
                                  GIMP_TOOL_HANDLE_SIZE_CROSS,
                                  GIMP_TOOL_HANDLE_SIZE_CROSS,
                                  GIMP_HANDLE_ANCHOR_CENTER);
diff --git a/app/tools/gimpperspectiveclonetool.h b/app/tools/gimpperspectiveclonetool.h
index 8ab7015ed8..d0c4697b61 100644
--- a/app/tools/gimpperspectiveclonetool.h
+++ b/app/tools/gimpperspectiveclonetool.h
@@ -38,21 +38,23 @@ typedef struct _GimpPerspectiveCloneToolClass GimpPerspectiveCloneToolClass;
 
 struct _GimpPerspectiveCloneTool
 {
-  GimpBrushTool   parent_instance;
+  GimpBrushTool        parent_instance;
 
-  GimpDisplay    *src_display;
-  gint            src_x;
-  gint            src_y;
+  GimpDisplay         *src_display;
+  gint                 src_x;
+  gint                 src_y;
 
-  GimpMatrix3     transform;      /*  transformation matrix            */
-  TransInfo       trans_info;     /*  transformation info              */
-  TransInfo       old_trans_info; /*  for cancelling a drag operation  */
+  GimpMatrix3          transform;      /*  transformation matrix            */
+  TransInfo            trans_info;     /*  transformation info              */
+  TransInfo            old_trans_info; /*  for cancelling a drag operation  */
 
-  gint            x1, y1;         /*  upper left hand coordinate       */
-  gint            x2, y2;         /*  lower right hand coords          */
+  gint                 x1, y1;         /*  upper left hand coordinate       */
+  gint                 x2, y2;         /*  lower right hand coords          */
 
-  GimpToolWidget *widget;
-  GimpToolWidget *grab_widget;
+  GimpCursorPrecision  saved_precision;
+
+  GimpToolWidget      *widget;
+  GimpToolWidget      *grab_widget;
 };
 
 struct _GimpPerspectiveCloneToolClass