[gimp/wip/Jehan/issue-498-quick-brush-edit] app: new modifier action to set brush size diameter.

[Jehan <jehanp src gnome org>]

commit fe1f9d600bcd564adc316f92a5b975aa56580e3f
Author: Jehan <jehan girinstud io>
Date:   Fri Aug 12 00:18:22 2022 +0200

    app: new modifier action to set brush size diameter.
    
    Actually I am renaming GIMP_MODIFIER_ACTION_BRUSH_PIXEL_SIZE into
    GIMP_MODIFIER_ACTION_BRUSH_RADIUS_PIXEL_SIZE, which allows to set the
    brush size on-canvas, starting from center to border.
    
    The new GIMP_MODIFIER_ACTION_BRUSH_PIXEL_SIZE now sets the brush size
    from one border to another.

 app/display/display-enums.c                |  2 ++
 app/display/display-enums.h                | 22 ++++++++++++----------
 app/display/gimpdisplayshell-tool-events.c | 30 ++++++++++++++++++++++++++----
 3 files changed, 40 insertions(+), 14 deletions(-)
---
diff --git a/app/display/display-enums.c b/app/display/display-enums.c
index db317dddbc..84e719d993 100644
--- a/app/display/display-enums.c
+++ b/app/display/display-enums.c
@@ -605,6 +605,7 @@ gimp_modifier_action_get_type (void)
     { GIMP_MODIFIER_ACTION_LAYER_PICKING, "GIMP_MODIFIER_ACTION_LAYER_PICKING", "layer-picking" },
     { GIMP_MODIFIER_ACTION_MENU, "GIMP_MODIFIER_ACTION_MENU", "menu" },
     { GIMP_MODIFIER_ACTION_BRUSH_PIXEL_SIZE, "GIMP_MODIFIER_ACTION_BRUSH_PIXEL_SIZE", "brush-pixel-size" },
+    { GIMP_MODIFIER_ACTION_BRUSH_RADIUS_PIXEL_SIZE, "GIMP_MODIFIER_ACTION_BRUSH_RADIUS_PIXEL_SIZE", 
"brush-radius-pixel-size" },
     { GIMP_MODIFIER_ACTION_BRUSH_SIZE, "GIMP_MODIFIER_ACTION_BRUSH_SIZE", "brush-size" },
     { 0, NULL, NULL }
   };
@@ -619,6 +620,7 @@ gimp_modifier_action_get_type (void)
     { GIMP_MODIFIER_ACTION_LAYER_PICKING, NC_("modifier-action", "Pick a layer"), NULL },
     { GIMP_MODIFIER_ACTION_MENU, NC_("modifier-action", "Display the menu"), NULL },
     { GIMP_MODIFIER_ACTION_BRUSH_PIXEL_SIZE, NC_("modifier-action", "Change brush size in canvas pixels"), 
NULL },
+    { GIMP_MODIFIER_ACTION_BRUSH_RADIUS_PIXEL_SIZE, NC_("modifier-action", "Change brush radius' size in 
canvas pixels"), NULL },
     { GIMP_MODIFIER_ACTION_BRUSH_SIZE, NC_("modifier-action", "Change brush size relatively"), NULL },
     { 0, NULL, NULL }
   };
diff --git a/app/display/display-enums.h b/app/display/display-enums.h
index 82d2dd7dd2..c251441837 100644
--- a/app/display/display-enums.h
+++ b/app/display/display-enums.h
@@ -267,16 +267,18 @@ GType gimp_modifier_action_get_type (void) G_GNUC_CONST;
 
 typedef enum
 {
-  GIMP_MODIFIER_ACTION_NONE,             /*< desc="No action"                          >*/
-  GIMP_MODIFIER_ACTION_PANNING,          /*< desc="Pan"                                >*/
-  GIMP_MODIFIER_ACTION_ZOOMING,          /*< desc="Zoom"                               >*/
-  GIMP_MODIFIER_ACTION_ROTATING,         /*< desc="Rotate"                             >*/
-  GIMP_MODIFIER_ACTION_STEP_ROTATING,    /*< desc="Rotate by 15 degree steps"          >*/
-  GIMP_MODIFIER_ACTION_LAYER_PICKING,    /*< desc="Pick a layer"                       >*/
-
-  GIMP_MODIFIER_ACTION_MENU,             /*< desc="Display the menu"                   >*/
-  GIMP_MODIFIER_ACTION_BRUSH_PIXEL_SIZE, /*< desc="Change brush size in canvas pixels" >*/
-  GIMP_MODIFIER_ACTION_BRUSH_SIZE        /*< desc="Change brush size relatively"       >*/
+  GIMP_MODIFIER_ACTION_NONE,                    /*< desc="No action"                          >*/
+  GIMP_MODIFIER_ACTION_PANNING,                 /*< desc="Pan"                                >*/
+  GIMP_MODIFIER_ACTION_ZOOMING,                 /*< desc="Zoom"                               >*/
+  GIMP_MODIFIER_ACTION_ROTATING,                /*< desc="Rotate"                             >*/
+  GIMP_MODIFIER_ACTION_STEP_ROTATING,           /*< desc="Rotate by 15 degree steps"          >*/
+  GIMP_MODIFIER_ACTION_LAYER_PICKING,           /*< desc="Pick a layer"                       >*/
+
+  GIMP_MODIFIER_ACTION_MENU,                    /*< desc="Display the menu"                   >*/
+
+  GIMP_MODIFIER_ACTION_BRUSH_PIXEL_SIZE,        /*< desc="Change brush size in canvas pixels" >*/
+  GIMP_MODIFIER_ACTION_BRUSH_RADIUS_PIXEL_SIZE, /*< desc="Change brush radius' size in canvas pixels" >*/
+  GIMP_MODIFIER_ACTION_BRUSH_SIZE               /*< desc="Change brush size relatively"       >*/
 } GimpModifierAction;
 
 
diff --git a/app/display/gimpdisplayshell-tool-events.c b/app/display/gimpdisplayshell-tool-events.c
index 06f4deae77..095f725ce8 100644
--- a/app/display/gimpdisplayshell-tool-events.c
+++ b/app/display/gimpdisplayshell-tool-events.c
@@ -592,6 +592,7 @@ gimp_display_shell_canvas_tool_events (GtkWidget        *canvas,
               case GIMP_MODIFIER_ACTION_LAYER_PICKING:
               case GIMP_MODIFIER_ACTION_BRUSH_SIZE:
               case GIMP_MODIFIER_ACTION_BRUSH_PIXEL_SIZE:
+              case GIMP_MODIFIER_ACTION_BRUSH_RADIUS_PIXEL_SIZE:
                 gimp_display_shell_start_scrolling (shell, event, state,
                                                     bevent->x, bevent->y);
               case GIMP_MODIFIER_ACTION_NONE:
@@ -743,6 +744,7 @@ gimp_display_shell_canvas_tool_events (GtkWidget        *canvas,
                 break;
               case GIMP_MODIFIER_ACTION_BRUSH_SIZE:
               case GIMP_MODIFIER_ACTION_BRUSH_PIXEL_SIZE:
+              case GIMP_MODIFIER_ACTION_BRUSH_RADIUS_PIXEL_SIZE:
                 gimp_display_shell_stop_scrolling (shell, event);
               case GIMP_MODIFIER_ACTION_NONE:
                 break;
@@ -1740,6 +1742,7 @@ gimp_display_shell_start_scrolling (GimpDisplayShell *shell,
         }
       break;
     case GIMP_MODIFIER_ACTION_BRUSH_PIXEL_SIZE:
+    case GIMP_MODIFIER_ACTION_BRUSH_RADIUS_PIXEL_SIZE:
     case GIMP_MODIFIER_ACTION_BRUSH_SIZE:
         {
           Gimp     *gimp        = gimp_display_get_gimp (shell->display);
@@ -1766,6 +1769,7 @@ gimp_display_shell_stop_scrolling (GimpDisplayShell *shell,
   switch (shell->mod_action)
     {
     case GIMP_MODIFIER_ACTION_BRUSH_PIXEL_SIZE:
+    case GIMP_MODIFIER_ACTION_BRUSH_RADIUS_PIXEL_SIZE:
     case GIMP_MODIFIER_ACTION_BRUSH_SIZE:
         {
           Gimp     *gimp       = gimp_display_get_gimp (shell->display);
@@ -1800,8 +1804,10 @@ gimp_display_shell_handle_scrolling (GimpDisplayShell *shell,
                                      gint              x,
                                      gint              y)
 {
-  GimpModifierAction mod_action = shell->mod_action;
-  gboolean           constrain  = FALSE;
+  GimpModifierAction mod_action      = shell->mod_action;
+  gboolean           constrain       = FALSE;
+  gboolean           size_update_pos = TRUE;
+  gdouble            size_multiplier = 1.0;
 
   if (mod_action == GIMP_MODIFIER_ACTION_NONE && shell->space_release_pending)
     {
@@ -1837,6 +1843,9 @@ gimp_display_shell_handle_scrolling (GimpDisplayShell *shell,
                                      shell->scroll_last_x - x,
                                      shell->scroll_last_y - y);
       break;
+    case GIMP_MODIFIER_ACTION_BRUSH_RADIUS_PIXEL_SIZE:
+      size_multiplier = 2.0;
+      size_update_pos = FALSE;
     case GIMP_MODIFIER_ACTION_BRUSH_PIXEL_SIZE:
     case GIMP_MODIFIER_ACTION_BRUSH_SIZE:
         {
@@ -1850,7 +1859,7 @@ gimp_display_shell_handle_scrolling (GimpDisplayShell *shell,
            * position.
            */
           size = (gint) (sqrt (pow ((x - shell->scroll_start_x) / shell->scale_x, 2) +
-                               pow ((y - shell->scroll_start_y) / shell->scale_y, 2)) * 2.0);
+                               pow ((y - shell->scroll_start_y) / shell->scale_y, 2)));
 
           /* TODO: different logics with "lock brush to view". */
           /* TODO 2: scale aware? */
@@ -1861,7 +1870,20 @@ gimp_display_shell_handle_scrolling (GimpDisplayShell *shell,
               GimpUIManager   *manager = gimp_image_window_get_ui_manager (window);
 
               gimp_display_shell_activate_action (manager, action,
-                                                  g_variant_new_double ((gdouble) size));
+                                                  g_variant_new_double ((gdouble) size * size_multiplier));
+
+              if (size_update_pos)
+                {
+                  GimpCoords display_coords;
+                  GimpCoords coords;
+
+                  display_coords.x = shell->scroll_start_x + (x - shell->scroll_start_x) / 2;
+                  display_coords.y = shell->scroll_start_y + (y - shell->scroll_start_y) / 2;
+                  gimp_display_shell_untransform_event_coords (shell,
+                                                               &display_coords, &coords,
+                                                               NULL);
+                  gimp_tool_oper_update (active_tool, &coords, 0, TRUE, display);
+                }
             }
           else
             {