[vte] lib: Keep track of unscaled cell size and report window size unscaled

[Christian Persch <chpe src gnome org>]

commit cfc406659b0ce45962ca07a86fbf3db956d8007f
Author: Hans Petter Jansson <hpj cl no>
Date:   Mon Oct 19 00:16:36 2020 +0200

    lib: Keep track of unscaled cell size and report window size unscaled
    
    This allows sixel image dimensions to be consistent when printed at
    different zoom levels.

 src/vte.cc         | 52 ++++++++++++++++++++++++++++++++++++++++++----------
 src/vtegtk.cc      |  4 ++--
 src/vteinternal.hh |  6 +++++-
 src/vteseq.cc      |  4 ++--
 4 files changed, 51 insertions(+), 15 deletions(-)
---
diff --git a/src/vte.cc b/src/vte.cc
index 496324bf..2cfa29da 100644
--- a/src/vte.cc
+++ b/src/vte.cc
@@ -3051,16 +3051,16 @@ Terminal::insert_image(vte::cairo::Surface image_surface) /* throws */
 
         auto const left = m_screen->cursor.col;
         auto const top = m_screen->cursor.row;
-        auto const width = (image_width_px + m_cell_width - 1) / m_cell_width;
-        auto const height = (image_height_px + m_cell_height - 1) / m_cell_height;
+        auto const width = (image_width_px + m_cell_width_unscaled - 1) / m_cell_width_unscaled;
+        auto const height = (image_height_px + m_cell_height_unscaled - 1) / m_cell_height_unscaled;
 
         m_screen->row_data->append_image(std::move(device_surface),
                                          image_width_px,
                                          image_height_px,
                                          left,
                                          top,
-                                         m_cell_width,
-                                         m_cell_height);
+                                         m_cell_width_unscaled,
+                                         m_cell_height_unscaled);
 
         /* Erase characters under the image */
         erase_image_rect(height, width);
@@ -7196,7 +7196,9 @@ Terminal::widget_mouse_leave(vte::platform::MouseEvent const& event)
  * here. Similarly, increase cell_width_scale to get nonzero char_spacing.{left,right}.
  */
 void
-Terminal::apply_font_metrics(int cell_width,
+Terminal::apply_font_metrics(int cell_width_unscaled,
+                                       int cell_height_unscaled,
+                                       int cell_width,
                                        int cell_height,
                                        int char_ascent,
                                        int char_descent,
@@ -7206,6 +7208,8 @@ Terminal::apply_font_metrics(int cell_width,
        bool resize = false, cresize = false;
 
        /* Sanity check for broken font changes. */
+        cell_width_unscaled = MAX(cell_width_unscaled, 1);
+        cell_height_unscaled = MAX(cell_height_unscaled, 2);
         cell_width = MAX(cell_width, 1);
         cell_height = MAX(cell_height, 2);
         char_ascent = MAX(char_ascent, 1);
@@ -7215,6 +7219,14 @@ Terminal::apply_font_metrics(int cell_width,
         char_height = char_ascent + char_descent;
 
        /* Change settings, and keep track of when we've changed anything. */
+        if (cell_width_unscaled != m_cell_width_unscaled) {
+                cresize = true;
+                m_cell_width_unscaled = cell_width_unscaled;
+       }
+        if (cell_height_unscaled != m_cell_height_unscaled) {
+                cresize = true;
+                m_cell_height_unscaled = cell_height_unscaled;
+       }
         if (cell_width != m_cell_width) {
                resize = cresize = true;
                 m_cell_width = cell_width;
@@ -7263,8 +7275,8 @@ Terminal::apply_font_metrics(int cell_width,
                         /* Update pixel size of PTY. */
                         pty()->set_size(m_row_count,
                                         m_column_count,
-                                        m_cell_height,
-                                        m_cell_width);
+                                        m_cell_height_unscaled,
+                                        m_cell_width_unscaled);
                 }
                emit_char_size_changed(m_cell_width, m_cell_height);
        }
@@ -7281,10 +7293,23 @@ Terminal::ensure_font()
                        set_font_desc(m_unscaled_font_desc.get());
                }
                if (m_fontdirty) {
+                        int cell_width_unscaled, cell_height_unscaled;
                         int cell_width, cell_height;
                         int char_ascent, char_descent;
                         GtkBorder char_spacing;
                        m_fontdirty = false;
+
+                        if (!_vte_double_equal(m_font_scale, 1.)) {
+                                m_draw.set_text_font(
+                                                     m_widget,
+                                                     m_unscaled_font_desc.get(),
+                                                     m_cell_width_scale,
+                                                     m_cell_height_scale);
+                                m_draw.get_text_metrics(
+                                                        &cell_width_unscaled, &cell_height_unscaled,
+                                                        nullptr, nullptr, nullptr);
+                        }
+
                        m_draw.set_text_font(
                                                  m_widget,
                                                  m_fontdesc.get(),
@@ -7294,7 +7319,14 @@ Terminal::ensure_font()
                                                     &cell_width, &cell_height,
                                                     &char_ascent, &char_descent,
                                                     &char_spacing);
-                        apply_font_metrics(cell_width, cell_height,
+
+                        if (_vte_double_equal(m_font_scale, 1.)) {
+                                cell_width_unscaled = cell_width;
+                                cell_height_unscaled = cell_height;
+                        }
+
+                        apply_font_metrics(cell_width_unscaled, cell_height_unscaled,
+                                           cell_width, cell_height,
                                            char_ascent, char_descent,
                                            char_spacing);
                }
@@ -7609,8 +7641,8 @@ Terminal::set_size(long columns,
                  */
                if (!pty()->set_size(rows,
                                      columns,
-                                     m_cell_height,
-                                     m_cell_width)) {
+                                     m_cell_height_unscaled,
+                                     m_cell_width_unscaled)) {
                         // nothing we can do here
                 }
                refresh_size();
diff --git a/src/vtegtk.cc b/src/vtegtk.cc
index 3666857f..6fed1718 100644
--- a/src/vtegtk.cc
+++ b/src/vtegtk.cc
@@ -3116,8 +3116,8 @@ try
         _vte_pty_set_size(pty.get(),
                           impl->m_row_count,
                           impl->m_column_count,
-                          impl->m_cell_height,
-                          impl->m_cell_width,
+                          impl->m_cell_height_unscaled,
+                          impl->m_cell_width_unscaled,
                           nullptr);
 
         return pty.release();
diff --git a/src/vteinternal.hh b/src/vteinternal.hh
index 1e01305a..a590b13c 100644
--- a/src/vteinternal.hh
+++ b/src/vteinternal.hh
@@ -703,6 +703,8 @@ public:
         GtkBorder m_char_padding{0, 0, 0, 0};
         long m_cell_width{0};
         long m_cell_height{0};
+        long m_cell_width_unscaled{0};
+        long m_cell_height_unscaled{0};
 
         /* We allow the cell's text to draw a bit outside the cell at the top
          * and bottom. The following two functions return how much is the
@@ -1134,7 +1136,9 @@ public:
 
         void ensure_font();
         void update_font();
-        void apply_font_metrics(int cell_width,
+        void apply_font_metrics(int cell_width_unscaled,
+                                int cell_height_unscaled,
+                                int cell_width,
                                 int cell_height,
                                 int char_ascent,
                                 int char_descent,
diff --git a/src/vteseq.cc b/src/vteseq.cc
index 6f174502..d1bd3c37 100644
--- a/src/vteseq.cc
+++ b/src/vteseq.cc
@@ -8813,8 +8813,8 @@ Terminal::XTERM_WM(vte::parser::Sequence const& seq)
                 break;
 
         case VTE_XTERM_WM_GET_WINDOW_SIZE_PIXELS: {
-                int width = m_row_count * m_cell_height;
-                int height = m_column_count * m_cell_width;
+                int width = m_row_count * m_cell_height_unscaled;
+                int height = m_column_count * m_cell_width_unscaled;
                 reply(seq, VTE_REPLY_XTERM_WM, {4, height, width});
                 break;
         }