[gimp/gimp-2-8] app: make switching paint tools to color picker mode more robust

[Michael Natterer <mitch src gnome org>]

commit e2284c6aa56c454b3cc8dc852d001a2eddbd3b53
Author: Michael Natterer <mitch gimp org>
Date:   Wed Nov 16 13:16:24 2016 +0100

    app: make switching paint tools to color picker mode more robust
    
    Don't rely on the exact modifier being pressed or released. Instead,
    check if only the right modifier is pressed after *each* modifier
    change, and switch to color picking if it is; disable color picking
    otherwise. This greatly reduces the risk of missing the user's wish to
    pick colors because of other modifiers being pressed and released in
    whatever order.
    
    Probably fixes bug #734743.
    
    (cherry picked from commit 014fdb87e57dcd2bbba6b2aa18371475aef98b4e)

 app/tools/gimppainttool.c |   57 +++++++++++++++++++++++----------------------
 1 files changed, 29 insertions(+), 28 deletions(-)
---
diff --git a/app/tools/gimppainttool.c b/app/tools/gimppainttool.c
index 9c52335..9282d5a 100644
--- a/app/tools/gimppainttool.c
+++ b/app/tools/gimppainttool.c
@@ -453,40 +453,41 @@ gimp_paint_tool_modifier_key (GimpTool        *tool,
   GimpPaintTool *paint_tool = GIMP_PAINT_TOOL (tool);
   GimpDrawTool  *draw_tool  = GIMP_DRAW_TOOL (tool);
 
-  if (key != gimp_get_constrain_behavior_mask ())
-    return;
-
   if (paint_tool->pick_colors && ! paint_tool->draw_line)
     {
-      if (press)
+      if ((state & gimp_get_all_modifiers_mask ()) ==
+          gimp_get_constrain_behavior_mask ())
         {
-          GimpToolInfo *info = gimp_get_tool_info (display->gimp,
-                                                   "gimp-color-picker-tool");
-
-          if (GIMP_IS_TOOL_INFO (info))
+          if (! gimp_color_tool_is_enabled (GIMP_COLOR_TOOL (tool)))
             {
-              if (gimp_draw_tool_is_active (draw_tool))
-                gimp_draw_tool_stop (draw_tool);
-
-              gimp_color_tool_enable (GIMP_COLOR_TOOL (tool),
-                                      GIMP_COLOR_OPTIONS (info->tool_options));
+              GimpToolInfo *info = gimp_get_tool_info (display->gimp,
+                                                       "gimp-color-picker-tool");
 
-              switch (GIMP_COLOR_TOOL (tool)->pick_mode)
+              if (GIMP_IS_TOOL_INFO (info))
                 {
-                case GIMP_COLOR_PICK_MODE_FOREGROUND:
-                  gimp_tool_push_status (tool, display,
-                                         _("Click in any image to pick the "
-                                           "foreground color"));
-                  break;
-
-                case GIMP_COLOR_PICK_MODE_BACKGROUND:
-                  gimp_tool_push_status (tool, display,
-                                         _("Click in any image to pick the "
-                                           "background color"));
-                  break;
-
-                default:
-                  break;
+                  if (gimp_draw_tool_is_active (draw_tool))
+                    gimp_draw_tool_stop (draw_tool);
+
+                  gimp_color_tool_enable (GIMP_COLOR_TOOL (tool),
+                                          GIMP_COLOR_OPTIONS (info->tool_options));
+
+                  switch (GIMP_COLOR_TOOL (tool)->pick_mode)
+                    {
+                    case GIMP_COLOR_PICK_MODE_FOREGROUND:
+                      gimp_tool_push_status (tool, display,
+                                             _("Click in any image to pick the "
+                                               "foreground color"));
+                      break;
+
+                    case GIMP_COLOR_PICK_MODE_BACKGROUND:
+                      gimp_tool_push_status (tool, display,
+                                             _("Click in any image to pick the "
+                                               "background color"));
+                      break;
+
+                    default:
+                      break;
+                    }
                 }
             }
         }