/*
 * Copyright (C) 2016 Alberts Muktupāvels
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#include "config.h"

#include <gtk/gtk.h>
#include <stdlib.h>
#include <string.h>

#include "meta-rectangle-private.h"
#include "meta-frame-layout-private.h"
#include "meta-frame-style-private.h"
#include "meta-theme-gtk-private.h"
#include "meta-theme.h"

struct _MetaThemeGtk
{
  MetaThemeImpl   parent;

  MetaFrameStyle *styles[META_FRAME_TYPE_LAST];
};

G_DEFINE_TYPE (MetaThemeGtk, meta_theme_gtk, META_TYPE_THEME_IMPL)

static void
meta_theme_gtk_dispose (GObject *object)
{
  MetaThemeGtk *gtk;
  gint i;

  gtk = META_THEME_GTK (object);

  for (i = 0; i < META_FRAME_TYPE_LAST; i++)
    {
      if (gtk->styles[i] != NULL)
        {
          meta_frame_style_unref (gtk->styles[i]);
          gtk->styles[i] = NULL;
        }
    }

  G_OBJECT_CLASS (meta_theme_gtk_parent_class)->dispose (object);
}

static gboolean
meta_theme_gtk_load (MetaThemeImpl  *impl,
                     const gchar    *name,
                     GError        **error)
{
  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);

  return TRUE;
}

static void
get_margin (GtkStyleContext *style,
            GtkBorder       *border)
{
  GtkStateFlags state;

  state = gtk_style_context_get_state (style);

  gtk_style_context_get_margin (style, state, border);
}

static void
get_padding_and_border (GtkStyleContext *style,
                        GtkBorder       *border)
{
  GtkBorder tmp;
  GtkStateFlags state = gtk_style_context_get_state (style);

  gtk_style_context_get_border (style, state, border);
  gtk_style_context_get_padding (style, state, &tmp);

  border->left += tmp.left;
  border->top += tmp.top;
  border->right += tmp.right;
  border->bottom += tmp.bottom;
}

static void
get_min_size (GtkStyleContext *style,
              GtkRequisition  *requisition)
{
  gtk_style_context_get (style, gtk_style_context_get_state (style),
                         "min-width", &requisition->width,
                         "min-height", &requisition->height,
                         NULL);
}

static void
get_shadow_extents (GtkStyleContext *style,
                    GtkBorder       *border)
{
  GdkRectangle clip;

  gtk_render_background_get_clip (style, 0, 0, 0, 0, &clip);

  border->left = abs (clip.x);
  border->top = abs (clip.y);
  border->right = clip.width - border->left;
  border->bottom = clip.height - border->top;
}

static void
frame_layout_sync_with_style (MetaFrameLayout *layout,
                              MetaStyleInfo   *style_info,
                              gboolean         composited,
                              MetaFrameFlags   flags)
{
  GtkStyleContext *style;
  GtkBorder border;
  GtkRequisition requisition;
  int border_radius, max_radius;

  meta_style_info_set_flags (style_info, flags);

  style = meta_style_info_get_style (style_info, META_STYLE_ELEMENT_DECORATION);
  get_padding_and_border (style, &layout->gtk.frame_border);
  scale_border (&layout->gtk.frame_border, layout->title_scale);

  if (composited)
    {
      /* With compositing manager: margin is resize area */
      get_margin (style, &layout->invisible_resize_border);
      get_shadow_extents (style, &layout->gtk.shadow_border);

      gtk_style_context_get (style, gtk_style_context_get_state (style),
                             "border-radius", &border_radius,
                             NULL);
      /* GTK+ currently does not allow us to look up radii of individual
       * corners; however we don't clip the client area, so with the
       * current trend of using small/no visible frame borders, most
       * themes should work fine with this.
       */
      layout->top_left_corner_rounded_radius = border_radius;
      layout->top_right_corner_rounded_radius = border_radius;
      max_radius = MIN (layout->gtk.frame_border.bottom, layout->gtk.frame_border.left);
      layout->bottom_left_corner_rounded_radius = MAX (border_radius, max_radius);
      max_radius = MIN (layout->gtk.frame_border.bottom, layout->gtk.frame_border.left);
      layout->bottom_right_corner_rounded_radius = MAX (border_radius, max_radius);
    }
  else
    {
      /* Without compositing manager we can not have invisible border */
      layout->invisible_resize_border.top = 0;
      layout->invisible_resize_border.bottom = 0;
      layout->invisible_resize_border.left = 0;
      layout->invisible_resize_border.right = 0;

      layout->gtk.shadow_border.top = 0;
      layout->gtk.shadow_border.bottom = 0;
      layout->gtk.shadow_border.left = 0;
      layout->gtk.shadow_border.right = 0;

      layout->top_left_corner_rounded_radius = 0;
      layout->top_right_corner_rounded_radius = 0;
      layout->bottom_left_corner_rounded_radius = 0;
      layout->bottom_right_corner_rounded_radius = 0;

      /* Without compositing manager: margin is part of border */
      get_margin (style, &border);

      layout->gtk.frame_border.left += border.left;
      layout->gtk.frame_border.right += border.right;
      layout->gtk.frame_border.top += border.top;
      layout->gtk.frame_border.bottom += border.bottom;
    }

  if (layout->hide_buttons)
    layout->gtk.icon_size = 0;

  if (!layout->has_title && layout->hide_buttons)
    return; /* border-only - be done */

  style = meta_style_info_get_style (style_info, META_STYLE_ELEMENT_TITLEBAR);
  get_min_size (style, &layout->gtk.titlebar_min_size);
  get_padding_and_border (style, &layout->gtk.titlebar_border);
  scale_border (&layout->gtk.titlebar_border, layout->title_scale);

  style = meta_style_info_get_style (style_info, META_STYLE_ELEMENT_TITLE);
  get_margin (style, &layout->gtk.title_margin);
  scale_border (&layout->gtk.title_margin, layout->title_scale);

  style = meta_style_info_get_style (style_info, META_STYLE_ELEMENT_BUTTON);
  get_min_size (style, &layout->gtk.button_min_size);
  get_padding_and_border (style, &layout->button_border);
  scale_border (&layout->button_border, layout->title_scale);

  get_margin (style, &layout->gtk.button_margin);
  scale_border (&layout->gtk.button_margin, layout->title_scale);

  style = meta_style_info_get_style (style_info, META_STYLE_ELEMENT_IMAGE);
  get_min_size (style, &requisition);
  get_padding_and_border (style, &border);
  scale_border (&border, layout->title_scale);

  layout->button_border.left += border.left;
  layout->button_border.right += border.right;
  layout->button_border.top += border.top;
  layout->button_border.bottom += border.bottom;

  get_margin (style, &border);
  layout->button_border.left += border.left;
  layout->button_border.right += border.right;
  layout->button_border.top += border.top;
  layout->button_border.bottom += border.bottom;

  layout->gtk.button_min_size.width = MAX (layout->gtk.button_min_size.width,
                                           requisition.width);
  layout->gtk.button_min_size.height = MAX (layout->gtk.button_min_size.height,
                                            requisition.height);
}

static MetaFrameStyle *
meta_theme_gtk_get_frame_style (MetaThemeImpl  *impl,
                                MetaFrameType   type,
                                MetaFrameFlags  flags)
{
  MetaThemeGtk *gtk;

  gtk = META_THEME_GTK (impl);

  return gtk->styles[type];
}

static void
meta_theme_gtk_get_frame_borders (MetaThemeImpl    *impl,
                                  MetaFrameLayout  *layout,
                                  MetaStyleInfo    *style_info,
                                  gint              text_height,
                                  MetaFrameFlags    flags,
                                  MetaFrameType     type,
                                  MetaFrameBorders *borders)
{
  gboolean composited;
  gint scale;
  gint title_height;
  gint buttons_height;
  gint content_height;

  composited = meta_theme_impl_get_composited (impl);
  frame_layout_sync_with_style (layout, style_info, composited, flags);

  meta_frame_borders_clear (borders);

  /* For a full-screen window, we don't have any borders, visible or not. */
  if (flags & META_FRAME_FULLSCREEN)
    return;

  g_return_if_fail (layout != NULL);

  if (!layout->has_title)
    text_height = 0;

  /* Scale geometry for HiDPI, see comment in meta_theme_gtk_draw_frame () */
  scale = meta_theme_impl_get_scale (impl);

  title_height = layout->gtk.title_margin.top +
                 text_height / scale +
                 layout->gtk.title_margin.bottom;

  buttons_height = MAX ((gint) layout->gtk.icon_size, layout->gtk.button_min_size.height) +
                   layout->gtk.button_margin.top + layout->button_border.top +
                   layout->gtk.button_margin.bottom + layout->button_border.bottom;

  content_height = MAX (title_height, buttons_height);
  content_height = MAX (content_height, layout->gtk.titlebar_min_size.height) +
                   layout->gtk.titlebar_border.top +
                   layout->gtk.titlebar_border.bottom;

  borders->visible.top = layout->gtk.frame_border.top + content_height;
  borders->visible.left = layout->gtk.frame_border.left;
  borders->visible.right = layout->gtk.frame_border.right;
  borders->visible.bottom = layout->gtk.frame_border.bottom;

  borders->shadow = layout->gtk.shadow_border;

  if (flags & META_FRAME_ALLOWS_HORIZONTAL_RESIZE)
    {
      borders->resize.left = layout->invisible_resize_border.left;
      borders->resize.right = layout->invisible_resize_border.right;
    }

  if (flags & META_FRAME_ALLOWS_VERTICAL_RESIZE)
    {
      borders->resize.bottom = layout->invisible_resize_border.bottom;

      if (type != META_FRAME_TYPE_ATTACHED)
        borders->resize.top = layout->invisible_resize_border.top;
    }

  borders->invisible.left = MAX (borders->shadow.left, borders->resize.left);
  borders->invisible.right = MAX (borders->shadow.right, borders->resize.right);
  borders->invisible.bottom = MAX (borders->shadow.bottom, borders->resize.bottom);
  borders->invisible.top = MAX (borders->shadow.top, borders->resize.top);

  borders->total.left = borders->invisible.left + borders->visible.left;
  borders->total.right = borders->invisible.right + borders->visible.right;
  borders->total.bottom = borders->invisible.bottom + borders->visible.bottom;
  borders->total.top = borders->invisible.top + borders->visible.top;

  scale_border (&borders->visible, scale);
  scale_border (&borders->shadow, scale);
  scale_border (&borders->resize, scale);
  scale_border (&borders->invisible, scale);
  scale_border (&borders->total, scale);
}

static void
meta_theme_gtk_calc_geometry (MetaThemeImpl     *impl,
                              MetaFrameLayout   *layout,
                              MetaStyleInfo     *style_info,
                              gint               text_height,
                              MetaFrameFlags     flags,
                              gint               client_width,
                              gint               client_height,
                              MetaButtonLayout  *button_layout,
                              MetaFrameType      type,
                              MetaFrameGeometry *fgeom)
{
  MetaFrameBorders borders;
  int i, n_left, n_right, n_left_spacers, n_right_spacers;
  int x;
  int button_y;
  int title_right_edge;
  int width, height;
  int scale;
  int content_height;
  int button_width, button_height;
  int min_size_for_rounding;

  META_THEME_IMPL_GET_CLASS (impl)->get_frame_borders (impl, layout,
                                                       style_info, text_height,
                                                       flags, type, &borders);

  fgeom->borders = borders;

  width = client_width + borders.total.left + borders.total.right;

  height = borders.total.top + borders.total.bottom;
  if (!(flags & META_FRAME_SHADED))
    height += client_height;

  fgeom->width = width;
  fgeom->height = height;

  /* Scale geometry for HiDPI, see comment in meta_theme_gtk_draw_frame () */
  scale = meta_theme_impl_get_scale (impl);

  content_height = borders.visible.top - layout->gtk.frame_border.top * scale;

  button_width = MAX ((gint) layout->gtk.icon_size, layout->gtk.button_min_size.width) +
                 layout->button_border.left + layout->button_border.right;
  button_height = MAX ((gint) layout->gtk.icon_size, layout->gtk.button_min_size.height) +
                  layout->button_border.top + layout->button_border.bottom;

  button_width *= scale;
  button_height *= scale;

  n_left = 0;
  n_right = 0;
  n_left_spacers = 0;
  n_right_spacers = 0;

  if (!layout->hide_buttons)
    {
      MetaButton *button;

      for (i = 0; i < button_layout->n_left_buttons; i++)
        {
          button = &button_layout->left_buttons[i];
          button->visible = is_button_visible (button, flags);

          if (button->visible)
            {
              if (button->type != META_BUTTON_TYPE_SPACER)
                n_left++;
              else
                n_left_spacers++;
            }
        }

      for (i = 0; i < button_layout->n_right_buttons; i++)
        {
          button = &button_layout->right_buttons[i];
          button->visible = is_button_visible (button, flags);

          if (button->visible)
            {
              if (button->type != META_BUTTON_TYPE_SPACER)
                n_right++;
              else
                n_right_spacers++;
            }
        }
    }
  else
    {
      for (i = 0; i < button_layout->n_left_buttons; i++)
        button_layout->left_buttons[i].visible = FALSE;

      for (i = 0; i < button_layout->n_right_buttons; i++)
        button_layout->right_buttons[i].visible = FALSE;
    }

  /* Be sure buttons fit */
  while (n_left > 0 || n_right > 0)
    {
      int space_used_by_buttons;
      int space_available;

      space_available = fgeom->width -
                        borders.total.left -
                        layout->gtk.titlebar_border.left * scale -
                        layout->gtk.titlebar_border.right * scale -
                        borders.total.right;

      space_used_by_buttons = 0;

      space_used_by_buttons += layout->gtk.button_margin.left * scale * n_left;
      space_used_by_buttons += button_width * n_left;
      space_used_by_buttons += layout->gtk.button_margin.right * scale * n_left;
      space_used_by_buttons += (button_width * 0.75) * n_left_spacers;
      space_used_by_buttons += layout->gtk.titlebar_spacing * scale * MAX (n_left - 1, 0);

      space_used_by_buttons += layout->gtk.button_margin.left * scale * n_right;
      space_used_by_buttons += button_width * n_right;
      space_used_by_buttons += layout->gtk.button_margin.right * scale * n_right;
      space_used_by_buttons += (button_width * 0.75) * n_right_spacers;
      space_used_by_buttons += layout->gtk.titlebar_spacing * scale * MAX (n_right - 1, 0);

      if (space_used_by_buttons <= space_available)
        break; /* Everything fits, bail out */

      /* First try to remove separators */
      if (n_left_spacers > 0)
        {
          if (strip_button (button_layout->left_buttons,
                            button_layout->n_left_buttons,
                            META_BUTTON_TYPE_SPACER))
            {
              n_left_spacers--;
              continue;
            }
          else
            {
              g_assert_not_reached ();
            }
        }
      else if (n_right_spacers > 0)
        {
          if (strip_button (button_layout->right_buttons,
                            button_layout->n_right_buttons,
                            META_BUTTON_TYPE_SPACER))
            {
              n_right_spacers--;
              continue;
            }
          else
            {
              g_assert_not_reached ();
            }
        }

      /* Otherwise we need to shave out a button. Shave
       * above, stick, shade, min, max, close, then menu (menu is most useful);
       * prefer the default button locations.
       */
      if (strip_buttons (button_layout, &n_left, &n_right))
        {
          continue;
        }
      else
        {
          g_error ("Could not find a button to strip. n_left = %d n_right = %d",
                   n_left, n_right);
        }
    }

  /* center buttons vertically */
  button_y = borders.invisible.top + layout->gtk.frame_border.top * scale +
             (content_height - button_height) / 2;

  /* right edge of farthest-right button */
  x = width - borders.invisible.right - layout->gtk.frame_border.right * scale -
      layout->gtk.titlebar_border.right * scale;

  for (i = button_layout->n_right_buttons - 1; i >= 0; i--)
    {
      MetaButton *button;
      GdkRectangle rect;

      button = &button_layout->right_buttons[i];

      if (button->visible == FALSE)
        continue;

      /* if we go negative, leave the buttons we don't get to as 0 - width */
      if (x < 0)
        break;

      x -= layout->gtk.button_margin.right * scale;

      rect.y = button_y;
      rect.width = button_width;
      rect.height = button_height;

      if (button->type == META_BUTTON_TYPE_SPACER)
        {
          rect.x = x - button_width * 0.75;
          rect.width *= 0.75;
        }
      else
        {
          rect.x = x - button_width;
        }

      button->rect.visible = rect;
      button->rect.clickable = rect;

      if ((flags & META_FRAME_MAXIMIZED || flags & META_FRAME_TILED_RIGHT) &&
          i == button_layout->n_right_buttons - 1)
        {
          gint extra_width;
          gint extra_height;

          extra_width = layout->gtk.button_margin.right * scale +
                        layout->gtk.frame_border.right * scale +
                        layout->gtk.titlebar_border.right * scale;

          /* FIXME: */
          extra_height = 0;

          button->rect.clickable.y -= extra_height;
          button->rect.clickable.width += extra_width;
          button->rect.clickable.height += extra_height;
        }

      x = rect.x - layout->gtk.button_margin.left * scale;
      x -= layout->gtk.titlebar_spacing * scale;
    }

  /* save right edge of titlebar for later use */
  title_right_edge = x;

  /* Now x changes to be position from the left and we go through
   * the left-side buttons
   */
  x = borders.invisible.left + layout->gtk.frame_border.left * scale +
      layout->gtk.titlebar_border.left * scale;

  for (i = 0; i < button_layout->n_left_buttons; i++)
    {
      MetaButton *button;
      GdkRectangle rect;

      button = &button_layout->left_buttons[i];

      if (button->visible == FALSE)
        continue;

      rect.x = x + layout->gtk.button_margin.left * scale;
      rect.y = button_y;
      rect.width = button_width;
      rect.height = button_height;

      if (button->type == META_BUTTON_TYPE_SPACER)
        rect.width *= 0.75;

      button->rect.visible = rect;
      button->rect.clickable = rect;

      if ((flags & META_FRAME_MAXIMIZED || flags & META_FRAME_TILED_LEFT) &&
          i == 0)
        {
          gint extra_width;
          gint extra_height;

          extra_width = layout->gtk.button_margin.left * scale +
                        layout->gtk.frame_border.left * scale +
                        layout->gtk.titlebar_border.left * scale;

          /* FIXME: */
          extra_height = 0;

          button->rect.clickable.x -= extra_width;
          button->rect.clickable.y -= extra_height;
          button->rect.clickable.width += extra_width;
          button->rect.clickable.height += extra_height;
        }

      x = rect.x + rect.width + layout->gtk.button_margin.right * scale;
      x += layout->gtk.titlebar_spacing * scale;
    }

  /* Center vertically in the available content area */
  fgeom->title_rect.x = x;
  fgeom->title_rect.y = borders.invisible.top + layout->gtk.frame_border.top * scale +
                        (content_height - text_height) / 2;
  fgeom->title_rect.width = title_right_edge - fgeom->title_rect.x;
  fgeom->title_rect.height = text_height;

  /* Nuke title if it won't fit */
  if (fgeom->title_rect.width < 0 ||
      fgeom->title_rect.height < 0)
    {
      fgeom->title_rect.width = 0;
      fgeom->title_rect.height = 0;
    }

  if (flags & META_FRAME_SHADED)
    min_size_for_rounding = 0;
  else
    min_size_for_rounding = 5 * scale;

  fgeom->top_left_corner_rounded_radius = 0;
  fgeom->top_right_corner_rounded_radius = 0;
  fgeom->bottom_left_corner_rounded_radius = 0;
  fgeom->bottom_right_corner_rounded_radius = 0;

  if (borders.visible.top + borders.visible.left >= min_size_for_rounding)
    fgeom->top_left_corner_rounded_radius = layout->top_left_corner_rounded_radius * scale;
  if (borders.visible.top + borders.visible.right >= min_size_for_rounding)
    fgeom->top_right_corner_rounded_radius = layout->top_right_corner_rounded_radius * scale;

  if (borders.visible.bottom + borders.visible.left >= min_size_for_rounding)
    fgeom->bottom_left_corner_rounded_radius = layout->bottom_left_corner_rounded_radius * scale;
  if (borders.visible.bottom + borders.visible.right >= min_size_for_rounding)
    fgeom->bottom_right_corner_rounded_radius = layout->bottom_right_corner_rounded_radius * scale;
}

static const char *
get_class_from_button_type (MetaButtonType type)
{
  if (type == META_BUTTON_TYPE_CLOSE)
    return "close";
  else if (type == META_BUTTON_TYPE_MAXIMIZE)
    return "maximize";
  else if (type == META_BUTTON_TYPE_MINIMIZE)
    return "minimize";

  return NULL;
}

static void
meta_theme_gtk_draw_frame (MetaThemeImpl           *impl,
                           MetaFrameStyle          *style,
                           MetaStyleInfo           *style_info,
                           cairo_t                 *cr,
                           const MetaFrameGeometry *fgeom,
                           PangoLayout             *title_layout,
                           MetaFrameFlags           flags,
                           const MetaButtonLayout  *button_layout,
                           GdkPixbuf               *mini_icon,
                           GdkPixbuf               *icon)
{
  gdouble scale;
  GtkStyleContext *context;
  GtkStateFlags state;
  MetaRectangleDouble visible_rect;
  MetaRectangleDouble titlebar_rect;
  const MetaFrameBorders *borders;
  gint side;

  /* We opt out of GTK+ HiDPI handling, so we have to do the scaling
   * ourselves; the nitty-gritty is a bit confusing, so here is an overview:
   *  - the values in MetaFrameLayout are always as they appear in the theme,
   *    i.e. unscaled
   *  - calculated values (borders, MetaFrameGeometry) include the scale - as
   *    the geometry is comprised of scaled decorations and the client size
   *    which we must not scale, we don't have another option
   *  - for drawing, we scale the canvas to have GTK+ render elements (borders,
   *    radii, ...) at the correct scale - as a result, we have to "unscale"
   *    the geometry again to not apply the scaling twice
   */
  scale = meta_theme_impl_get_scale (impl);
  cairo_scale (cr, scale, scale);

  borders = &fgeom->borders;

  visible_rect.x = borders->invisible.left / scale;
  visible_rect.y = borders->invisible.top / scale;
  visible_rect.width = (fgeom->width - borders->invisible.left - borders->invisible.right) / scale;
  visible_rect.height = (fgeom->height - borders->invisible.top - borders->invisible.bottom) / scale;

  meta_style_info_set_flags (style_info, flags);

  context = meta_style_info_get_style (style_info, META_STYLE_ELEMENT_DECORATION);
  gtk_render_background (context, cr,
                         visible_rect.x, visible_rect.y,
                         visible_rect.width, visible_rect.height);
  gtk_render_frame (context, cr,
                    visible_rect.x, visible_rect.y,
                    visible_rect.width, visible_rect.height);

  if (flags & META_FRAME_FULLSCREEN)
    return;

  titlebar_rect.x = visible_rect.x + borders->visible.left / scale;
  titlebar_rect.y = visible_rect.y + style->layout->gtk.frame_border.top;
  titlebar_rect.width = visible_rect.width - (borders->visible.left + borders->visible.right) / scale;
  titlebar_rect.height = (borders->visible.top / scale) - style->layout->gtk.frame_border.top;

  context = meta_style_info_get_style (style_info, META_STYLE_ELEMENT_TITLEBAR);
  gtk_render_background (context, cr,
                         titlebar_rect.x, titlebar_rect.y,
                         titlebar_rect.width, titlebar_rect.height);
  gtk_render_frame (context, cr,
                    titlebar_rect.x, titlebar_rect.y,
                    titlebar_rect.width, titlebar_rect.height);

  if (style->layout->has_title && title_layout)
    {
      PangoRectangle logical;
      gdouble text_width;
      int x;
      int y;

      pango_layout_set_width (title_layout, -1);
      pango_layout_get_pixel_extents (title_layout, NULL, &logical);

      text_width = MIN(fgeom->title_rect.width / scale, logical.width);

      if (text_width < logical.width)
        pango_layout_set_width (title_layout, PANGO_SCALE * text_width);

      /* Center within the frame if possible */
      x = titlebar_rect.x + (titlebar_rect.width - text_width) / 2;
      y = titlebar_rect.y + (titlebar_rect.height - logical.height) / 2;

      if (x < fgeom->title_rect.x / scale)
        x = fgeom->title_rect.x / scale;
      else if (x + text_width > (fgeom->title_rect.x + fgeom->title_rect.width) / scale)
        x = (fgeom->title_rect.x + fgeom->title_rect.width) / scale - text_width;

      cairo_save (cr);

      cairo_rectangle (cr,
                       fgeom->title_rect.x / scale,
                       fgeom->title_rect.y / scale,
                       fgeom->title_rect.width / scale,
                       fgeom->title_rect.height / scale);
      cairo_clip (cr);

      context = meta_style_info_get_style (style_info, META_STYLE_ELEMENT_TITLE);
      gtk_render_layout (context, cr, x, y, title_layout);

      cairo_restore (cr);
    }

  context = meta_style_info_get_style (style_info, META_STYLE_ELEMENT_BUTTON);
  state = gtk_style_context_get_state (context);

  for (side = 0; side < 2; side++)
    {
      MetaButton *buttons;
      gint n_buttons;
      gint i;

      if (side == 0)
        {
          buttons = button_layout->left_buttons;
          n_buttons = button_layout->n_left_buttons;
        }
      else if (side == 1)
        {
          buttons = button_layout->right_buttons;
          n_buttons = button_layout->n_right_buttons;
        }
      else
        {
          g_assert_not_reached ();
        }

      for (i = 0; i < n_buttons; i++)
        {
          MetaButton *button;
          gdouble x;
          gdouble y;
          gdouble width;
          gdouble height;
          const gchar *button_class;
          const gchar *icon_name;
          GdkPixbuf *pixbuf;

          button = &buttons[i];

          x = button->rect.visible.x / scale;
          y = button->rect.visible.y / scale;
          width = button->rect.visible.width / scale;
          height = button->rect.visible.height / scale;

          if (!button->visible || button->type == META_BUTTON_TYPE_SPACER ||
              width <= 0 || height <= 0)
            {
              continue;
            }

          button_class = get_class_from_button_type (button->type);

          if (button_class)
            gtk_style_context_add_class (context, button_class);

          if (button->state == META_BUTTON_STATE_PRELIGHT)
            gtk_style_context_set_state (context, state | GTK_STATE_PRELIGHT);
          else if (button->state == META_BUTTON_STATE_PRESSED)
            gtk_style_context_set_state (context, state | GTK_STATE_ACTIVE);
          else
            gtk_style_context_set_state (context, state);

          cairo_save (cr);

          gtk_render_background (context, cr, x, y, width, height);
          gtk_render_frame (context, cr, x, y, width, height);

          icon_name = NULL;
          pixbuf = NULL;

          switch (button->type)
            {
              case META_BUTTON_TYPE_CLOSE:
                icon_name = "window-close-symbolic";
                break;
              case META_BUTTON_TYPE_MAXIMIZE:
                if (flags & META_FRAME_MAXIMIZED)
                  icon_name = "window-restore-symbolic";
                else
                  icon_name = "window-maximize-symbolic";
                break;
              case META_BUTTON_TYPE_MINIMIZE:
                icon_name = "window-minimize-symbolic";
                break;
              case META_BUTTON_TYPE_MENU:
                icon_name = "open-menu-symbolic";
                break;
              case META_BUTTON_TYPE_SPACER:
              case META_BUTTON_TYPE_LAST:
              default:
                break;
            }

          if (icon_name)
            {
              GtkIconTheme *theme;
              GtkIconInfo *info;

              theme = gtk_icon_theme_get_default ();
              info = gtk_icon_theme_lookup_icon_for_scale (theme, icon_name,
                                                           style->layout->gtk.icon_size,
                                                           scale, 0);

              g_assert (pixbuf == NULL);
              pixbuf = gtk_icon_info_load_symbolic_for_context (info, context, NULL, NULL);
              g_object_unref (info);
            }

          if (pixbuf)
            {
              gdouble pwidth;
              gdouble pheight;
              gdouble px;
              gdouble py;
              gdouble scale_x;
              gdouble scale_y;

              pwidth = gdk_pixbuf_get_width (pixbuf) / scale;
              pheight = gdk_pixbuf_get_height (pixbuf) / scale;
              px = x + (width - pwidth) / 2;
              py = y + (height - pheight) / 2;

              scale_x = pwidth / style->layout->gtk.icon_size / scale;
              scale_y = pheight / style->layout->gtk.icon_size / scale;

              cairo_translate (cr, px, py);
              cairo_scale (cr, scale_x, scale_y);
              gdk_cairo_set_source_pixbuf (cr, pixbuf, 0, 0);
              cairo_paint (cr);

              g_object_unref (pixbuf);
            }

          cairo_restore (cr);

          if (button_class)
            gtk_style_context_remove_class (context, button_class);

          gtk_style_context_set_state (context, state);
        }
    }
}

static void
meta_theme_gtk_class_init (MetaThemeGtkClass *gtk_class)
{
  GObjectClass *object_class;
  MetaThemeImplClass *impl_class;

  object_class = G_OBJECT_CLASS (gtk_class);
  impl_class = META_THEME_IMPL_CLASS (gtk_class);

  object_class->dispose = meta_theme_gtk_dispose;

  impl_class->load = meta_theme_gtk_load;
  impl_class->get_frame_style = meta_theme_gtk_get_frame_style;
  impl_class->get_frame_borders = meta_theme_gtk_get_frame_borders;
  impl_class->calc_geometry = meta_theme_gtk_calc_geometry;
  impl_class->draw_frame = meta_theme_gtk_draw_frame;
}

static void
meta_theme_gtk_init (MetaThemeGtk *gtk)
{
  MetaFrameType type;

  for (type = 0; type < META_FRAME_TYPE_LAST; type++)
    {
      MetaFrameStyle *style;

      style = meta_frame_style_new (NULL);
      style->layout = meta_frame_layout_new ();

      switch (type)
        {
          case META_FRAME_TYPE_NORMAL:
          case META_FRAME_TYPE_DIALOG:
          case META_FRAME_TYPE_MODAL_DIALOG:
          case META_FRAME_TYPE_ATTACHED:
            break;

          case META_FRAME_TYPE_MENU:
          case META_FRAME_TYPE_UTILITY:
            style->layout->title_scale = PANGO_SCALE_SMALL;
            break;

          case META_FRAME_TYPE_BORDER:
            style->layout->has_title = FALSE;
            style->layout->hide_buttons = TRUE;
            break;

          case META_FRAME_TYPE_LAST:
          default:
            g_assert_not_reached ();
        }

      gtk->styles[type] = style;
    }
}
