GLK: FROTZ: Added skeleton classes for ZMachine windows

7 files changed, 313 insertions, 120 deletions

diff --git a/engines/glk/frotz/glk_interface.cpp b/engines/glk/frotz/glk_interface.cpp
index 4aa2ba4e78..514435aaf0 100644
--- a/engines/glk/frotz/glk_interface.cpp
+++ b/engines/glk/frotz/glk_interface.cpp
@@ -33,13 +33,11 @@ namespace Frotz {
 
 GlkInterface::GlkInterface(OSystem *syst, const GlkGameDescription &gameDesc) :
 		GlkAPI(syst, gameDesc),
-		_pics(nullptr), oldstyle(0), curstyle(0), cury(1), curx(1), fixforced(0),
-		curr_fg(-2), curr_bg(-2), curr_font(1), prev_font(1), temp_font(0),
-		curr_status_ht(0), mach_status_ht(0), gos_status(nullptr), gos_upper(nullptr),
-		gos_lower(nullptr), gos_curwin(nullptr), gos_linepending(0), gos_linebuf(nullptr),
-		gos_linewin(nullptr), gos_channel(nullptr), cwin(0), mwin(0), mouse_x(0), mouse_y(0),
-		menu_selected(0), enable_wrapping(false), enable_scripting(false),
-		enable_scrolling(false), enable_buffering(false), next_sample(0), next_volume(0),
+		_pics(nullptr), oldstyle(0), curstyle(0), cury(1), curx(1), fixforced(0), curr_fg(-2), curr_bg(-2),
+		curr_font(1), prev_font(1), temp_font(0), curr_status_ht(0), mach_status_ht(0), gos_status(nullptr),
+		gos_curwin(nullptr), gos_linepending(0), gos_linebuf(nullptr), gos_linewin(nullptr),
+		gos_channel(nullptr), cwin(0), mwin(0), mouse_x(0), mouse_y(0), menu_selected(0), enable_wrapping(false),
+		enable_scripting(false), enable_scrolling(false), enable_buffering(false), next_sample(0), next_volume(0),
 		_soundLocked(false), _soundPlaying(false) {
 	Common::fill(&statusline[0], &statusline[256], '\0');
 }
@@ -103,47 +101,14 @@ void GlkInterface::initialize() {
 	 * Get the screen size
 	 */
 
-	gos_lower = glk_window_open(0, 0, 0, wintype_TextGrid, 0);
-	if (!gos_lower)
-		gos_lower = glk_window_open(0, 0, 0, wintype_TextBuffer, 0);
-	glk_window_get_size(gos_lower, &width, &height);
-	glk_window_close(gos_lower, nullptr);
+	_wp._lower = glk_window_open(0, 0, 0, wintype_TextGrid, 0);
+	if (!_wp._lower)
+		_wp._lower = glk_window_open(0, 0, 0, wintype_TextBuffer, 0);
+	glk_window_get_size(_wp._lower, &width, &height);
+	glk_window_close(_wp._lower, nullptr);
 
 	gos_channel = nullptr;
 
-	/*
-	 * Icky magic bit setting
-	 */
-
-	if (h_version == V3 && _tandyBit)
-		h_config |= CONFIG_TANDY;
-
-	if (h_version == V3 && gos_upper)
-		h_config |= CONFIG_SPLITSCREEN;
-
-	if (h_version == V3 && !gos_upper)
-		h_config |= CONFIG_NOSTATUSLINE;
-
-	if (h_version >= V4)
-		h_config |= CONFIG_BOLDFACE | CONFIG_EMPHASIS |
-		CONFIG_FIXED | CONFIG_TIMEDINPUT | CONFIG_COLOUR;
-
-	if (h_version >= V5)
-		h_flags &= ~(GRAPHICS_FLAG | MOUSE_FLAG | MENU_FLAG);
-
-	if ((h_version >= 5) && (h_flags & SOUND_FLAG))
-		h_flags |= SOUND_FLAG;
-
-	if ((h_version == 3) && (h_flags & OLD_SOUND_FLAG))
-		h_flags |= OLD_SOUND_FLAG;
-
-	if ((h_version == 6) && (_sound != 0))
-		h_config |= CONFIG_SOUND;
-
-	if (h_version >= V5 && (h_flags & UNDO_FLAG))
-		if (_undo_slots == 0)
-			h_flags &= ~UNDO_FLAG;
-
 	h_screen_cols = width;
 	h_screen_rows = height;
 
@@ -180,14 +145,48 @@ void GlkInterface::initialize() {
 	if (_storyId == BEYOND_ZORK)
 		showBeyondZorkTitle();
 
-	gos_lower = glk_window_open(0, 0, 0, wintype_TextBuffer, 0);
-	gos_upper = glk_window_open(gos_lower,
-		winmethod_Above | winmethod_Fixed,
-		0,
-		wintype_TextGrid, 0);
+	_wp._lower = glk_window_open(0, 0, 0, wintype_TextBuffer, 0);
+	_wp._upper = glk_window_open(_wp._lower, winmethod_Above | winmethod_Fixed, 0, wintype_TextGrid, 0);
 
-	glk_set_window(gos_lower);
-	gos_curwin = gos_lower;
+	glk_set_window(_wp._lower);
+	gos_curwin = _wp._lower;
+
+	/*
+	 * Icky magic bit setting
+	 */
+
+	if (h_version == V3 && _tandyBit)
+		h_config |= CONFIG_TANDY;
+
+	if (h_version == V3 && _wp._upper)
+		h_config |= CONFIG_SPLITSCREEN;
+
+	if (h_version == V3 && !_wp._upper)
+		h_config |= CONFIG_NOSTATUSLINE;
+
+	if (h_version >= V4)
+		h_config |= CONFIG_BOLDFACE | CONFIG_EMPHASIS |
+		CONFIG_FIXED | CONFIG_TIMEDINPUT | CONFIG_COLOUR;
+
+	if (h_version >= V5)
+		h_flags &= ~(GRAPHICS_FLAG | MOUSE_FLAG | MENU_FLAG);
+
+	if ((h_version >= 5) && (h_flags & SOUND_FLAG))
+		h_flags |= SOUND_FLAG;
+
+	if ((h_version == 3) && (h_flags & OLD_SOUND_FLAG))
+		h_flags |= OLD_SOUND_FLAG;
+
+	if ((h_version == 6) && (_sound != 0))
+		h_config |= CONFIG_SOUND;
+
+	if (h_version >= V5 && (h_flags & UNDO_FLAG))
+		if (_undo_slots == 0)
+			h_flags &= ~UNDO_FLAG;
+
+	/*
+	 * Miscellaneous
+	 */
 
 	// Set the screen colors
 	garglk_set_zcolors(_defaultForeground, _defaultBackground);
@@ -199,7 +198,7 @@ void GlkInterface::initialize() {
 	// since the arrow keys the original used are in use now for cycling prior commands
 	if (_storyId == BEYOND_ZORK) {
 		uint32 KEYCODES[2] = { keycode_PageUp, keycode_PageDown };
-		glk_set_terminators_line_event(gos_lower, KEYCODES, 2);
+		glk_set_terminators_line_event(_wp._lower, KEYCODES, 2);
 	}
 }
 
@@ -322,12 +321,12 @@ void GlkInterface::start_next_sample() {
 
 void GlkInterface::gos_update_width() {
 	uint width;
-	if (gos_upper) {
-		glk_window_get_size(gos_upper, &width, nullptr);
+	if (_wp._upper) {
+		glk_window_get_size(_wp._upper, &width, nullptr);
 		h_screen_cols = width;
 		SET_BYTE(H_SCREEN_COLS, width);
 		if ((uint)curx > width) {
-			glk_window_move_cursor(gos_upper, 0, cury - 1);
+			glk_window_move_cursor(_wp._upper, 0, cury - 1);
 			curx = 1;
 		}
 	}
@@ -337,8 +336,8 @@ void GlkInterface::gos_update_height() {
 	uint height_upper;
 	uint height_lower;
 	if (gos_curwin) {
-		glk_window_get_size(gos_upper, nullptr, &height_upper);
-		glk_window_get_size(gos_lower, nullptr, &height_lower);
+		glk_window_get_size(_wp._upper, nullptr, &height_upper);
+		glk_window_get_size(_wp._lower, nullptr, &height_lower);
 		h_screen_rows = height_upper + height_lower + 1;
 		SET_BYTE(H_SCREEN_ROWS, h_screen_rows);
 	}
@@ -346,11 +345,11 @@ void GlkInterface::gos_update_height() {
 
 void GlkInterface::reset_status_ht() {
 	uint height;
-	if (gos_upper) {
-		glk_window_get_size(gos_upper, nullptr, &height);
+	if (_wp._upper) {
+		glk_window_get_size(_wp._upper, nullptr, &height);
 		if ((uint)mach_status_ht != height) {
 			glk_window_set_arrangement(
-				glk_window_get_parent(gos_upper),
+				glk_window_get_parent(_wp._upper),
 				winmethod_Above | winmethod_Fixed,
 				mach_status_ht, nullptr);
 		}
@@ -359,23 +358,21 @@ void GlkInterface::reset_status_ht() {
 
 void GlkInterface::erase_window(zword w) {
 	if (w == 0)
-		glk_window_clear(gos_lower);
-	else if (gos_upper) {
+		glk_window_clear(_wp._lower);
+	else if (_wp._upper) {
 #ifdef GARGLK
-		garglk_set_reversevideo_stream(
-			glk_window_get_stream(gos_upper),
-			true);
+		garglk_set_reversevideo_stream(glk_window_get_stream(_wp._upper), true);
 #endif /* GARGLK */
 		
 		memset(statusline, ' ', sizeof statusline);
-		glk_window_clear(gos_upper);
+		glk_window_clear(_wp._upper);
 		reset_status_ht();
 		curr_status_ht = 0;
 	}
 }
 
 void GlkInterface::split_window(zword lines) {
-	if (!gos_upper)
+	if (!_wp._upper)
 		return;
 
 	// The top line is always set for V1 to V3 games
@@ -385,10 +382,10 @@ void GlkInterface::split_window(zword lines) {
 	if (!lines || lines > curr_status_ht) {
 		uint height;
 
-		glk_window_get_size(gos_upper, nullptr, &height);
+		glk_window_get_size(_wp._upper, nullptr, &height);
 		if (lines != height)
 			glk_window_set_arrangement(
-				glk_window_get_parent(gos_upper),
+				glk_window_get_parent(_wp._upper),
 				winmethod_Above | winmethod_Fixed,
 				lines, nullptr);
 		curr_status_ht = lines;
@@ -396,13 +393,13 @@ void GlkInterface::split_window(zword lines) {
 	mach_status_ht = lines;
 	if (cury > lines)
 	{
-		glk_window_move_cursor(gos_upper, 0, 0);
+		glk_window_move_cursor(_wp._upper, 0, 0);
 		curx = cury = 1;
 	}
 	gos_update_width();
 
 	if (h_version == V3)
-		glk_window_clear(gos_upper);
+		glk_window_clear(_wp._upper);
 }
 
 void GlkInterface::restart_screen() {
@@ -471,9 +468,9 @@ void GlkInterface::smartstatusline() {
 	memcpy(buf + 1 + scoreofs, c, scorelen * sizeof(zchar));
 	memcpy(buf + 1, a, roomlen * sizeof(zchar));
 
-	glk_window_move_cursor(gos_upper, 0, 0);
+	glk_window_move_cursor(_wp._upper, 0, 0);
 	glk_put_buffer_uni(buf, h_screen_cols);
-	glk_window_move_cursor(gos_upper, cury - 1, curx - 1);
+	glk_window_move_cursor(_wp._upper, cury - 1, curx - 1);
 }
 
 void GlkInterface::gos_cancel_pending_line() {
@@ -510,7 +507,7 @@ void GlkInterface::os_draw_picture(int picture, winid_t win, const Common::Rect
 
 zchar GlkInterface::os_read_key(int timeout, bool show_cursor) {
 	event_t ev;
-	winid_t win = gos_curwin ? gos_curwin : gos_lower;
+	winid_t win = gos_curwin ? gos_curwin : _wp._lower;
 
 	if (gos_linepending)
 		gos_cancel_pending_line();
@@ -536,7 +533,7 @@ zchar GlkInterface::os_read_key(int timeout, bool show_cursor) {
 
 	glk_request_timer_events(0);
 
-	if (gos_upper && mach_status_ht < curr_status_ht)
+	if (_wp._upper && mach_status_ht < curr_status_ht)
 		reset_status_ht();
 	curr_status_ht = 0;
 
@@ -558,7 +555,7 @@ zchar GlkInterface::os_read_key(int timeout, bool show_cursor) {
 
 zchar GlkInterface::os_read_line(int max, zchar *buf, int timeout, int width, int continued) {
 	event_t ev;
-	winid_t win = gos_curwin ? gos_curwin : gos_lower;
+	winid_t win = gos_curwin ? gos_curwin : _wp._lower;
 
 	if (!continued && gos_linepending)
 		gos_cancel_pending_line();
@@ -592,7 +589,7 @@ zchar GlkInterface::os_read_line(int max, zchar *buf, int timeout, int width, in
 	buf[ev.val1] = '\0';
 
 	// If the upper status line area was expanded to show a text box/quotation, restore it back
-	if (gos_upper && mach_status_ht < curr_status_ht)
+	if (_wp._upper && mach_status_ht < curr_status_ht)
 		reset_status_ht();
 	curr_status_ht = 0;
 
diff --git a/engines/glk/frotz/glk_interface.h b/engines/glk/frotz/glk_interface.h
index 4d69151560..5027edb4d5 100644
--- a/engines/glk/frotz/glk_interface.h
+++ b/engines/glk/frotz/glk_interface.h
@@ -25,6 +25,7 @@
 
 #include "glk/glk_api.h"
 #include "glk/frotz/mem.h"
+#include "glk/frotz/windows.h"
 
 namespace Glk {
 namespace Frotz {
@@ -67,9 +68,8 @@ public:
 	int curr_status_ht;
 	int mach_status_ht;
 
+	Windows _wp;
 	winid_t gos_status;
-	winid_t gos_upper;
-	winid_t gos_lower;
 	winid_t gos_curwin;
 	int gos_linepending;
 	zchar *gos_linebuf;
diff --git a/engines/glk/frotz/processor_screen.cpp b/engines/glk/frotz/processor_screen.cpp
index 33c91081ca..60672c85ab 100644
--- a/engines/glk/frotz/processor_screen.cpp
+++ b/engines/glk/frotz/processor_screen.cpp
@@ -26,7 +26,7 @@ namespace Glk {
 namespace Frotz {
 
 void Processor::screen_mssg_on() {
-	if (gos_curwin == gos_lower) {
+	if (gos_curwin == _wp._lower) {
 		oldstyle = curstyle;
 		glk_set_style(style_Preformatted);
 		glk_put_string("\n    ");
@@ -34,7 +34,7 @@ void Processor::screen_mssg_on() {
 }
 
 void Processor::screen_mssg_off() {
-	if (gos_curwin == gos_lower) {
+	if (gos_curwin == _wp._lower) {
 		glk_put_char('\n');
 		zargs[0] = 0;
 		z_set_text_style();
@@ -98,7 +98,7 @@ uint32 Processor::zchar_to_unicode_rune(zchar c) {
 void Processor::screen_char(zchar c) {
 	if (gos_linepending && (gos_curwin == gos_linewin)) {
 		gos_cancel_pending_line();
-		if (gos_curwin == gos_upper) {
+		if (gos_curwin == _wp._upper) {
 			curx = 1;
 			cury ++;
 		}
@@ -119,7 +119,7 @@ void Processor::screen_char(zchar c) {
 		fixforced = false;
 	}
 
-	if (gos_upper && gos_curwin == gos_upper) {
+	if (_wp._upper && gos_curwin == _wp._upper) {
 		if (c == '\n' || c == ZC_RETURN) {
 			glk_put_char('\n');
 			curx = 1;
@@ -151,7 +151,7 @@ void Processor::screen_char(zchar c) {
 				curx++;
 			}
 		}
-	} else if (gos_curwin == gos_lower) {
+	} else if (gos_curwin == _wp._lower) {
 		if (c == ZC_RETURN)
 			glk_put_char('\n');
 		else {
@@ -200,7 +200,7 @@ store((zword)os_buffer_screen((zargs[0] == (zword)-1) ? -1 : zargs[0]));
 void Processor::z_erase_line() {
 	int i;
 
-	if (gos_upper && gos_curwin == gos_upper) {
+	if (_wp._upper && gos_curwin == _wp._upper) {
 		for (i = 0; i < h_screen_cols + 1 - curx; i++)
 			glk_put_char(' ');
 		glk_window_move_cursor(gos_curwin, curx - 1, cury - 1);
@@ -211,34 +211,33 @@ void Processor::z_erase_window() {
 	short w = zargs[0];
 	if (w == -2)
 	{
-		if (gos_upper) {
-			glk_set_window(gos_upper);
+		if (_wp._upper) {
+			glk_set_window(_wp._upper);
 #ifdef GARGLK
 			garglk_set_zcolors(curr_fg, curr_bg);
 #endif /* GARGLK */
-			glk_window_clear(gos_upper);
+			glk_window_clear(_wp._upper);
 			glk_set_window(gos_curwin);
 		}
-		glk_window_clear(gos_lower);
+		glk_window_clear(_wp._lower);
 	}
 	if (w == -1)
 	{
-		if (gos_upper) {
-			glk_set_window(gos_upper);
+		if (_wp._upper) {
+			glk_set_window(_wp._upper);
 #ifdef GARGLK
 			garglk_set_zcolors(curr_fg, curr_bg);
 #endif /* GARGLK */
-			glk_window_clear(gos_upper);
+			glk_window_clear(_wp._upper);
 		}
-		glk_window_clear(gos_lower);
+		glk_window_clear(_wp._lower);
 		split_window(0);
-		glk_set_window(gos_lower);
-		gos_curwin = gos_lower;
+		glk_set_window(_wp._lower);
+		gos_curwin = _wp._lower;
 	}
-	if (w == 0)
-		glk_window_clear(gos_lower);
-	if (w == 1 && gos_upper)
-		glk_window_clear(gos_upper);
+
+	if (w >= 0 && _wp[w])
+		glk_window_clear(_wp[w]);
 }
 
 void Processor::z_get_cursor() {
@@ -260,7 +259,7 @@ void Processor::z_print_table() {
 
 	// Write text in width x height rectangle
 	for (i = 0; i < zargs[2]; i++, curx = xs, cury++) {
-		glk_window_move_cursor(cwin == 0 ? gos_lower : gos_upper, xs - 1, cury - 1);
+		glk_window_move_cursor(_wp[cwin], xs - 1, cury - 1);
 
 		for (j = 0; j < zargs[1]; j++) {
 			LOW_BYTE(addr, c);
@@ -384,7 +383,7 @@ void Processor::z_set_font() {
 
 void Processor::z_set_cursor() {
 	int x = (int16)zargs[1], y = (int16)zargs[0];
-	assert(gos_upper);
+	assert(_wp._upper);
 
 	flush_buffer();
 
@@ -394,7 +393,8 @@ void Processor::z_set_cursor() {
 	}
 
 	if (!x || !y) {
-		Point cursorPos = gos_upper->getCursor();
+		winid_t win = _wp._upper;
+		Point cursorPos = win->getCursor();
 		if (!x)
 			x = cursorPos.x;
 		if (!y)
@@ -409,7 +409,7 @@ void Processor::z_set_cursor() {
 		reset_status_ht();
 	}
 
-	glk_window_move_cursor(gos_upper, curx - 1, cury - 1);
+	glk_window_move_cursor(_wp._upper, curx - 1, cury - 1);
 }
 
 void Processor::z_set_text_style() {
@@ -468,12 +468,12 @@ void Processor::z_set_window() {
 	cwin = zargs[0];
 
 	if (cwin == 0) {
-		glk_set_window(gos_lower);
-		gos_curwin = gos_lower;
+		glk_set_window(_wp._lower);
+		gos_curwin = _wp._lower;
 	} else {
-		if (gos_upper)
-			glk_set_window(gos_upper);
-		gos_curwin = gos_upper;
+		if (_wp._upper)
+			glk_set_window(_wp._upper);
+		gos_curwin = _wp._upper;
 	}
 
 	if (cwin == 0)
@@ -500,7 +500,7 @@ void Processor::z_show_status() {
 
 	bool brief = false;
 
-	if (!gos_upper)
+	if (!_wp._upper)
 		return;
 
 	// One V5 game (Wishbringer Solid Gold) contains this opcode by accident,
@@ -519,15 +519,15 @@ void Processor::z_show_status() {
 	LOW_WORD(addr, global2);
 
 	// Move to top of the status window, and print in reverse style.
-	glk_set_window(gos_upper);
-	gos_curwin = gos_upper;
+	glk_set_window(_wp._upper);
+	gos_curwin = _wp._upper;
 
 #ifdef GARGLK
 	garglk_set_reversevideo(true);
 #endif /* GARGLK */
 
 	curx = cury = 1;
-	glk_window_move_cursor(gos_upper, 0, 0);
+	glk_window_move_cursor(_wp._upper, 0, 0);
 
 	// If the screen width is below 55 characters then we have to use
 	// the brief status line format
@@ -580,8 +580,8 @@ void Processor::z_show_status() {
 	pad_status_line (0);
 
 	// Return to the lower window
-	glk_set_window(gos_lower);
-	gos_curwin = gos_lower;
+	glk_set_window(_wp._lower);
+	gos_curwin = _wp._lower;
 }
 
 void Processor::z_split_window() {
diff --git a/engines/glk/frotz/processor_windows.cpp b/engines/glk/frotz/processor_windows.cpp
index c0a1e3feee..ad16bbafe6 100644
--- a/engines/glk/frotz/processor_windows.cpp
+++ b/engines/glk/frotz/processor_windows.cpp
@@ -51,7 +51,8 @@ void Processor::z_draw_picture() {
 	if (!x || !y) {
 		// Currently I only support getting the cursor for the text grid area
 		assert(cwin == 1);
-		Point cursPos = gos_upper->getCursor();
+		winid_t win = _wp._upper;
+		Point cursPos = win->getCursor();
 		// use cursor column if x-coordinate is 0
 		if (!x)
 			x = cursPos.x;
@@ -82,18 +83,18 @@ void Processor::z_draw_picture() {
 			if (_storyId == ARTHUR && pic == 54)
 			delta = h_screen_width / 160;
 
-			os_draw_picture(mapper[i].pic1, gos_lower, Point(x + delta, y + height1));
-			os_draw_picture(mapper[i].pic2, gos_lower, Point(x + width1 - width2 - delta, y + height1));
+			os_draw_picture(mapper[i].pic1, _wp._lower, Point(x + delta, y + height1));
+			os_draw_picture(mapper[i].pic2, _wp._lower, Point(x + width1 - width2 - delta, y + height1));
 		}
 	}
 
-	os_draw_picture(pic, gos_lower, Point(x, y));
+	os_draw_picture(pic, _wp._lower, Point(x, y));
 
 	if (_storyId == SHOGUN && pic == 3) {
 		uint height, width;
 
 		os_picture_data(59, &height, &width);
-		os_draw_picture(59, gos_lower, Point(h_screen_width - width + 1, y));
+		os_draw_picture(59, _wp._lower, Point(h_screen_width - width + 1, y));
 	}
 }
 
diff --git a/engines/glk/frotz/windows.cpp b/engines/glk/frotz/windows.cpp
new file mode 100644
index 0000000000..8bdfafd879
--- /dev/null
+++ b/engines/glk/frotz/windows.cpp
@@ -0,0 +1,97 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ */
+
+#include "glk/frotz/screen.h"
+#include "glk/conf.h"
+#include "common/file.h"
+#include "graphics/fonts/ttf.h"
+#include "image/bmp.h"
+
+namespace Glk {
+namespace Frotz {
+
+FrotzScreen::FrotzScreen() : Glk::Screen() {
+	g_conf->_tStyles[style_User1].font = CUSTOM;
+	g_conf->_gStyles[style_User1].font = CUSTOM;
+	g_conf->_tStyles[style_User2].font = CUSTOM2;
+}
+
+void FrotzScreen::loadFonts(Common::Archive *archive) {
+	Screen::loadFonts(archive);
+
+	// Add character graphics font
+	Image::BitmapDecoder decoder;
+	Common::File f;
+	if (!f.open("infocom_graphics.bmp", *archive))
+		error("Could not load font");
+
+	Common::Point fontSize(_fonts[0]->getMaxCharWidth(), _fonts[0]->getFontHeight());
+	decoder.loadStream(f);
+	_fonts.push_back(new Frotz::BitmapFont(*decoder.getSurface(), fontSize));
+	f.close();
+
+	// Add Runic font. It provides cleaner versions of the runic characters in the
+	// character graphics font
+	if (!f.open("NotoSansRunic-Regular.ttf", *archive))
+		error("Could not load font");
+
+	_fonts.push_back(Graphics::loadTTFFont(f, g_conf->_propInfo._size, Graphics::kTTFSizeModeCharacter));
+	f.close();
+}
+
+/*--------------------------------------------------------------------------*/
+
+BitmapFont::BitmapFont(const Graphics::Surface &src, const Common::Point &size,
+		uint srcWidth, uint srcHeight, unsigned char startingChar) :
+		_startingChar(startingChar), _size(size) {
+	assert(src.format.bytesPerPixel == 1);
+	assert((src.w % srcWidth) == 0);
+	assert((src.h % srcHeight) == 0);
+
+	// Set up a characters array
+	_chars.resize((src.w / srcWidth) * (src.h / srcHeight));
+
+	// Iterate through loading characters
+	Common::Rect r(srcWidth, srcHeight);
+	int charsPerRow = src.w / srcWidth;
+	for (uint idx = 0; idx < _chars.size(); ++idx) {
+		r.moveTo((idx % charsPerRow) * srcWidth, (idx / charsPerRow) * srcHeight);
+
+		_chars[idx].create(size.x, size.y, src.format);
+		_chars[idx].transBlitFrom(src, r, Common::Rect(0, 0, size.x, size.y));
+	}
+}
+
+void BitmapFont::drawChar(Graphics::Surface *dst, uint32 chr, int x, int y, uint32 color) const {
+	const Graphics::ManagedSurface &c = _chars[chr - _startingChar];
+	for (int yCtr = 0; yCtr < c.h; ++yCtr) {
+		const byte *srcP = (const byte *)c.getBasePtr(0, yCtr);
+
+		for (int xCtr = 0; xCtr < c.w; ++xCtr, ++srcP) {
+			if (!*srcP)
+				dst->hLine(x + xCtr, y + yCtr, x + xCtr, color);
+		}
+	}
+}
+
+} // End of namespace Scott
+} // End of namespace Glk
diff --git a/engines/glk/frotz/windows.h b/engines/glk/frotz/windows.h
new file mode 100644
index 0000000000..566d2fd5c8
--- /dev/null
+++ b/engines/glk/frotz/windows.h
@@ -0,0 +1,97 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ */
+
+#ifndef GLK_FROTZ_WINDOWS
+#define GLK_FROTZ_WINDOWS
+
+namespace Glk {
+namespace Frotz {
+
+/**
+ * Represents one of the virtual windows
+ */
+class Window {
+private:
+	winid_t _win;
+public:
+	/**
+	 * Constructor
+	 */
+	Window() : _win(nullptr) {}
+
+	/**
+	 * Assignment operator
+	 */
+	Window &operator=(winid_t win) {
+		_win = win;
+		return *this;
+	}
+
+	/**
+	 * Cast operator for getting a Glk window
+	 */
+	operator winid_t() const { return _win; }
+
+	/**
+	 * Cast operator for testing if the window is valid (present)
+	 */
+	operator bool() const { return _win != nullptr; }
+
+	/**
+	 * Property access. There are the following properties defined by the spec:
+	 * 0  y coordinate    6   left margin size            12  font number
+	 * 1  x coordinate    7   right margin size           13  font size
+	 * 2  y size          8   newline interrupt routine   14  attributes
+	 * 3  x size          9   interrupt countdown         15  line count
+	 * 4  y cursor        10  text style                  16 true foreground colour
+	 * 5  x cursor        11  colour data                 17 true background colour
+	 */
+};
+
+/**
+ * The Z-machine has 8 virtual windows
+ */
+class Windows {
+private:
+	Window _windows[8];
+public:
+	Window &_lower;
+	Window &_upper;
+public:
+	/**
+	 * Constructor
+	 */
+	Windows() : _lower(_windows[0]), _upper(_windows[1]) {}
+
+	/**
+	 * Array access
+	 */
+	Window &operator[](uint idx) {
+		assert(idx < 8);
+		return _windows[idx];
+	}
+};
+
+} // End of namespace Frotz
+} // End of namespace Glk
+
+#endif
diff --git a/engines/glk/module.mk b/engines/glk/module.mk
index da3de68fde..38f19c5a8a 100644
--- a/engines/glk/module.mk
+++ b/engines/glk/module.mk
@@ -53,6 +53,7 @@ MODULE_OBJS := \
 	frotz/quetzal.o \
 	frotz/screen.o \
 	frotz/sound_folder.o \
+	frotz/windows.o \
 	glulxe/detection.o \
 	glulxe/glulxe.o \
 	magnetic/detection.o \