Add option to disable straight line preview w/Shift+Pencil tool

data/pref.xml

@@ -126,6 +126,7 @@
       <option id="auto_scroll" type="bool" default="true" />
       <option id="right_click_mode" type="RightClickMode" default="RightClickMode::PAINT_BGCOLOR" migrate="Options.RightClickMode" />
       <option id="auto_select_layer" type="bool" default="false" migrate="Options.AutoSelectLayer" />
+      <option id="straight_line_preview" type="bool" default="true" />
       <option id="play_once" type="bool" default="false" />
       <option id="play_all" type="bool" default="false" />
     </section>

data/strings/en.ini

@@ -309,6 +309,13 @@ zoom_from_center_with_keys = Zoom from center with keys
 show_scrollbars = Show scroll-bars in sprite editor
 show_scrollbars_tooltip = Show scroll-bars in all sprite editors.
 auto_scroll = Auto-scroll on editor edges
+straight_line_preview = Preview straight line inmediately on Pencil tool
+straight_line_preview_tooltip = <<<END
+On Pencil tool you can draw straight lines
+using Shift+click, with this option checked
+you will see the preview inmediately when
+the Shift key is pressed.
+END
 right_click = Right-click:
 editor_selection = Selection
 auto_opaque = Adjust opaque/transparent mode automatically

data/widgets/options.xml

@@ -84,6 +84,7 @@
           <check text="@.zoom_from_center_with_keys" id="zoom_from_center_with_keys" />
           <check text="@.show_scrollbars" id="show_scrollbars" tooltip="@.show_scrollbars_tooltip" />
           <check text="@.auto_scroll" id="auto_scroll" />
+          <check text="@.straight_line_preview" id="straight_line_preview" tooltip="@.straight_line_preview_tooltip" />
           <hbox>
             <label text="@.right_click" />
             <combobox id="right_click_behavior" expansive="true" />

src/app/commands/cmd_options.cpp

@@ -232,6 +232,9 @@ public:
     if (m_pref.editor.autoScroll())
       autoScroll()->setSelected(true);
 
+    if (m_pref.editor.straightLinePreview())
+      straightLinePreview()->setSelected(true);
+
     // Scope
     bgScope()->addItem("Background for New Documents");
     gridScope()->addItem("Grid for New Documents");
@@ -372,6 +375,7 @@ public:
     m_pref.editor.zoomFromCenterWithKeys(zoomFromCenterWithKeys()->isSelected());
     m_pref.editor.showScrollbars(showScrollbars()->isSelected());
     m_pref.editor.autoScroll(autoScroll()->isSelected());
+    m_pref.editor.straightLinePreview(straightLinePreview()->isSelected());
     m_pref.editor.zoomWithWheel(wheelZoom()->isSelected());
 #if __APPLE__
     m_pref.editor.zoomWithSlide(slideZoom()->isSelected());

src/app/ui/editor/drawing_state.cpp

@@ -141,7 +141,8 @@ bool DrawingState::onMouseUp(Editor* editor, MouseMessage* msg)
   // using Shift+click with the Pencil tool. When we release the mouse
   // button, if the Shift key is pressed, the whole ToolLoop starts
   // again.
-  checkStartDrawingStraightLine(editor);
+  if (Preferences::instance().editor.straightLinePreview())
+    checkStartDrawingStraightLine(editor);
   return true;
 }
 
@@ -204,7 +205,7 @@ bool DrawingState::onKeyUp(Editor* editor, KeyMessage* msg)
   // Cancel loop pressing Esc key...
   if (msg->scancode() == ui::kKeyEsc ||
       // Cancel "Shift on freehand" line preview when the Shift key is
-      // released and the user didn't press the mouse button..
+      // released and the user didn't press the mouse button.
       (m_type == DrawingType::LineFreehand &&
        !m_mousePressedReceived &&
        !editor->startStraightLineWithFreehandTool())) {

src/app/ui/editor/standby_state.cpp

@@ -316,6 +316,16 @@ bool StandbyState::onMouseDown(Editor* editor, MouseMessage* msg)
 
   // Start the Tool-Loop
   if (layer && (layer->isImage() || clickedInk->isSelection())) {
+    // Shift+click on Pencil tool starts a line onMouseDown() when the
+    // preview (onKeyDown) is disabled.
+    if (!Preferences::instance().editor.straightLinePreview() &&
+        checkStartDrawingStraightLine(editor)) {
+      // Send first mouse down to draw the straight line and start the
+      // freehand mode.
+      editor->getState()->onMouseDown(editor, msg);
+      return true;
+    }
+
     // Disable layer edges to avoid showing the modified cel
     // information by ExpandCelCanvas (i.e. the cel origin is changed
     // to 0,0 coordinate.)
@@ -490,7 +500,8 @@ bool StandbyState::onSetCursor(Editor* editor, const gfx::Point& mouseScreenPos)
 
 bool StandbyState::onKeyDown(Editor* editor, KeyMessage* msg)
 {
-  if (checkStartDrawingStraightLine(editor))
+  if (Preferences::instance().editor.straightLinePreview() &&
+      checkStartDrawingStraightLine(editor))
     return true;
   return false;
 }