[vte] widget: Add helpers to convert coordinates

[Christian Persch <chpe src gnome org>]

commit ca766131718a3a27cae93311e6042aa4450f4796
Author: Christian Persch <chpe gnome org>
Date:   Fri Dec 25 21:55:42 2015 +0100

    widget: Add helpers to convert coordinates
    
    Add helper functions to convert the event to grid and view coordinates,
    to convert between grid and view coordinates, and to check if
    grid and view coordinates are within the visible area.

 src/vte.cc         |  121 +++++++++++++++++++++++++++++++++++++++++++++------
 src/vteinternal.hh |   18 ++++++-
 2 files changed, 121 insertions(+), 18 deletions(-)
---
diff --git a/src/vte.cc b/src/vte.cc
index fadaad3..1825075 100644
--- a/src/vte.cc
+++ b/src/vte.cc
@@ -1849,28 +1849,119 @@ VteTerminalPrivate::regex_match_check(vte::grid::column_t column,
        return ret;
 }
 
+/*
+ * VteTerminalPrivate::view_coords_from_event:
+ * @event: a #GdkEvent
+ *
+ * Translates the event coordinates to view coordinates, by
+ * subtracting the padding and window offset.
+ * Coordinates < 0 or >= m_usable_view_extents.width() or .height()
+ * mean that the event coordinates are outside the usable area
+ * at that side; use view_coords_visible() to check for that.
+ */
+vte::view::coords
+VteTerminalPrivate::view_coords_from_event(GdkEvent const* event) const
+{
+        double x, y;
+        if (event == nullptr ||
+            ((reinterpret_cast<GdkEventAny const*>(event))->window != gtk_widget_get_window(m_widget)) ||
+            !gdk_event_get_coords(event, &x, &y))
+                return vte::view::coords(-1, -1);
+
+        return vte::view::coords(x - m_padding.left, y - m_padding.top);
+}
+
+/*
+ * VteTerminalPrivate::grid_coords_from_event:
+ * @event: a #GdkEvent
+ *
+ * Translates the event coordinates to view coordinates, by
+ * subtracting the padding and window offset.
+ * Coordinates < 0 or >= m_usable_view_extents.width() or .height()
+ * mean that the event coordinates are outside the usable area
+ * at that side; use grid_coords_visible() to check for that.
+ */
+vte::grid::coords
+VteTerminalPrivate::grid_coords_from_event(GdkEvent const* event) const
+{
+        return grid_coords_from_view_coords(view_coords_from_event(event));
+}
+
+/*
+ * VteTerminalPrivate::grid_coords_from_view_coords:
+ * @pos: the view coordinates
+ * @rowcol: the grid coordinates
+ *
+ * Translates view coordinates to grid coordinates. If the view coordinates point to
+ * cells that are not visible, may return any value < 0 or >= m_column_count, and
+ * < first_displayed_row() or > last_displayed_row(), resp.
+ */
+vte::grid::coords
+VteTerminalPrivate::grid_coords_from_view_coords(vte::view::coords const& pos) const
+{
+        vte::grid::column_t col;
+        if (pos.x >= 0 && pos.x < m_view_usable_extents.width())
+                col = pos.x / m_char_width;
+        else if (pos.x < 0)
+                col = -1;
+        else
+                col = m_column_count;
+
+        vte::grid::row_t row = pixel_to_row(pos.y);
+
+        return vte::grid::coords(row, col);
+}
+
+/*
+ * VteTerminalPrivate::view_coords_from_grid_coords:
+ * @rowcol: the grid coordinates
+ *
+ * Translates grid coordinates to view coordinates. If the view coordinates are
+ * outside the usable area, may return any value < 0 or >= m_usable_view_extents.
+ *
+ * Returns: %true if the coordinates are inside the usable area
+ */
+vte::view::coords
+VteTerminalPrivate::view_coords_from_grid_coords(vte::grid::coords const& rowcol) const
+{
+        return vte::view::coords(rowcol.column() * m_char_width,
+                                 row_to_pixel(rowcol.row()));
+}
+
+bool
+VteTerminalPrivate::view_coords_visible(vte::view::coords const& pos) const
+{
+        return pos.x >= 0 && pos.x < m_view_usable_extents.width() &&
+               pos.y >= 0 && pos.y < m_view_usable_extents.height();
+}
+
+bool
+VteTerminalPrivate::grid_coords_visible(vte::grid::coords const& rowcol) const
+{
+        return rowcol.column() >= 0 &&
+               rowcol.column() < m_column_count &&
+               rowcol.row() >= first_displayed_row() &&
+               rowcol.row() <= last_displayed_row();
+}
+
+vte::grid::coords
+VteTerminalPrivate::confine_grid_coords(vte::grid::coords& rowcol) const
+{
+        return vte::grid::coords(CLAMP(rowcol.row(), first_displayed_row(), last_displayed_row()),
+                                 CLAMP(rowcol.column(), 0, m_column_count - 1));
+}
+
 bool
 VteTerminalPrivate::rowcol_from_event(GdkEvent *event,
                                       long *column,
                                       long *row)
 {
-        double x, y;
-
-        if (event == NULL)
-                return FALSE;
-        if (((GdkEventAny*)event)->window != gtk_widget_get_window(m_widget))
-                return FALSE;
-        if (!gdk_event_get_coords(event, &x, &y))
-                return FALSE;
-
-        x -= m_padding.left;
-        y -= m_padding.top;
-        if (x < 0 || x >= m_column_count * m_char_width ||
-            y < 0 || y >= m_view_usable_extents.height())
+        auto rowcol = grid_coords_from_event(event);
+        if (!grid_coords_visible(rowcol))
                 return false;
-        *column = x / m_char_width;
-        *row = pixel_to_row(y);
 
+        *column = rowcol.column();
+        *row = rowcol.row();
         return true;
 }
 
diff --git a/src/vteinternal.hh b/src/vteinternal.hh
index 83b2db4..3b5b4a7 100644
--- a/src/vteinternal.hh
+++ b/src/vteinternal.hh
@@ -488,9 +488,6 @@ public:
         gssize get_preedit_width(bool left_only);
         gssize get_preedit_length(bool left_only);
 
-        void confine_coordinates(long *xp,
-                                 long *yp);
-
         void invalidate_cursor_once(bool periodic = false);
         void invalidate_cursor_periodic();
         void check_cursor_blink();
@@ -519,6 +516,21 @@ public:
         inline vte::view::coord_t get_allocated_width() const { return m_allocated_rect.width; }
         inline vte::view::coord_t get_allocated_height() const { return m_allocated_rect.height; }
 
+        vte::view::coords view_coords_from_event(GdkEvent const* event) const;
+        vte::grid::coords grid_coords_from_event(GdkEvent const* event) const;
+
+        vte::view::coords view_coords_from_grid_coords(vte::grid::coords const& rowcol) const;
+        vte::grid::coords grid_coords_from_view_coords(vte::view::coords const& pos) const;
+
+        bool view_coords_visible(vte::view::coords const& pos) const;
+        bool grid_coords_visible(vte::grid::coords const& rowcol) const;
+
+        vte::grid::coords confine_grid_coords(vte::grid::coords& rowcol) const;
+
+        void confine_coordinates(long *xp,
+                                 long *yp);
+
+
         void widget_paste(GdkAtom board);
         void widget_copy(VteSelection sel);
         void widget_paste_received(char const* text);