[gimp] app: more code in paint and brightness-contrast tool to port.

[Jehan <jehanp src gnome org>]

commit 1fa951127e6e999aba61ee13782a65e2bf8d0906
Author: Jehan <jehan girinstud io>
Date:   Sat Aug 1 18:24:15 2020 +0200

    app: more code in paint and brightness-contrast tool to port.
    
    These 2 tools only work on single drawable at once. Yet slowly getting
    rid of all usage of gimp_image_get_active_drawable().

 app/tools/gimpbrightnesscontrasttool.c | 14 ++++++++++----
 app/tools/gimppainttool-paint.c        |  7 ++++++-
 2 files changed, 16 insertions(+), 5 deletions(-)
---
diff --git a/app/tools/gimpbrightnesscontrasttool.c b/app/tools/gimpbrightnesscontrasttool.c
index d3a6fda414..4f43fcfecd 100644
--- a/app/tools/gimpbrightnesscontrasttool.c
+++ b/app/tools/gimpbrightnesscontrasttool.c
@@ -127,16 +127,20 @@ gimp_brightness_contrast_tool_initialize (GimpTool     *tool,
                                           GimpDisplay  *display,
                                           GError      **error)
 {
-  GimpBrightnessContrastTool *bc_tool  = GIMP_BRIGHTNESS_CONTRAST_TOOL (tool);
-  GimpImage                  *image    = gimp_display_get_image (display);
-  GimpDrawable               *drawable = gimp_image_get_active_drawable (image);
+  GimpBrightnessContrastTool *bc_tool   = GIMP_BRIGHTNESS_CONTRAST_TOOL (tool);
+  GimpImage                  *image     = gimp_display_get_image (display);
+  GList                      *drawables;
 
   if (! GIMP_TOOL_CLASS (parent_class)->initialize (tool, display, error))
     {
       return FALSE;
     }
 
-  if (gimp_drawable_get_component_type (drawable) == GIMP_COMPONENT_TYPE_U8)
+  drawables = gimp_image_get_selected_drawables (image);
+  /* Single drawable selection has been checked in parent initialize(). */
+  g_return_val_if_fail (g_list_length (drawables) == 1, FALSE);
+
+  if (gimp_drawable_get_component_type (drawables->data) == GIMP_COMPONENT_TYPE_U8)
     {
       gimp_prop_widget_set_factor (bc_tool->brightness_scale,
                                    127.0, 1.0, 8.0, 0);
@@ -151,6 +155,8 @@ gimp_brightness_contrast_tool_initialize (GimpTool     *tool,
                                    0.5, 0.01, 0.1, 3);
     }
 
+  g_list_free (drawables);
+
   return TRUE;
 }
 
diff --git a/app/tools/gimppainttool-paint.c b/app/tools/gimppainttool-paint.c
index 88cd526b97..7c0baebe1d 100644
--- a/app/tools/gimppainttool-paint.c
+++ b/app/tools/gimppainttool-paint.c
@@ -231,6 +231,7 @@ gimp_paint_tool_paint_start (GimpPaintTool     *paint_tool,
   GimpDisplayShell *shell;
   GimpImage        *image;
   GimpDrawable     *drawable;
+  GList            *drawables;
   GimpCoords        curr_coords;
   gint              off_x, off_y;
 
@@ -246,10 +247,14 @@ gimp_paint_tool_paint_start (GimpPaintTool     *paint_tool,
   core          = paint_tool->core;
   shell         = gimp_display_get_shell (display);
   image         = gimp_display_get_image (display);
-  drawable      = gimp_image_get_active_drawable (image);
+  drawables     = gimp_image_get_selected_drawables (image);
+
+  g_return_val_if_fail (g_list_length (drawables) == 1, FALSE);
 
   curr_coords = *coords;
 
+  drawable = drawables->data;
+  g_list_free (drawables);
   gimp_item_get_offset (GIMP_ITEM (drawable), &off_x, &off_y);
 
   curr_coords.x -= off_x;