1 files changed, 220 insertions, 15 deletions

diff --git a/char-table.c b/char-table.c
index da82544..076ef8f 100644
--- a/char-table.c
+++ b/char-table.c
@@ -1,39 +1,244 @@
 /* See LICENSE file for copyright and license details. */
 #include "common.h"
 
+#define FIRST_CHARACTER     0x0000u
+#define LAST_CHARACTER      0xFFFFu
+#define REFERENCE_CHARACTER "X"
+#define CELL_WIDTH_FACTOR   4
+#define CELL_HEIGHT_FACTOR  2
+#define CELL_X_CLEARANCE    2
+#define CELL_Y_CLEARANCE    2
+#define BASE_FONT_FAMILY    "Sans"
+#define BASE_FONT_SIZE      22
+
 G_DEFINE_TYPE(CharTable, gcmap_char_table, GTK_TYPE_DRAWING_AREA)
 
 
-static gboolean
+static int
+is_noncharacter(gunichar ch)
+{
+	return (0xFDD0u <= ch && ch <= 0xFDEFu) || (ch & 0xFFFEu) == 0xFFFEu;
+}
+
+
+static int
+is_printable_character(gunichar ch)
+{
+	return g_unichar_validate(ch) &&
+	       !g_unichar_iscntrl(ch) &&
+	       !g_unichar_iszerowidth(ch) &&
+	       !is_noncharacter(ch);
+}
+
+
+static void
+format_character(gunichar ch, char *buf)
+{
+	if (is_printable_character(ch))
+		buf[g_unichar_to_utf8(ch, buf)] = '\0';
+#ifdef TODO /* this part is just for testing */
+	else if (ch == 0x7Fu)
+		stpcpy(buf, "DELETE");
+	else
+		stpcpy(buf, "X");
+#else
+	else
+		buf[0u] = '\0';
+#endif
+}
+
+
+static void
+apply_font_size(CharTable *this, int size, int *text_w_out, int *text_h_out)
+{
+	pango_font_description_set_size(this->font, size * PANGO_SCALE);
+	pango_layout_set_font_description(this->layout, this->font);
+	pango_layout_context_changed(this->layout);
+	pango_layout_get_pixel_size(this->layout, text_w_out, text_h_out);
+}
+
+
+static void
+fit_text(CharTable *this, const char *text, int *text_w_out, int *text_h_out)
+{
+	int size, ok_size = 1;
+	double scale_x, scale_y, scale;
+
+	/* Set text to measure */
+	pango_layout_set_text(this->layout, text, -1);
+
+	/* Try default size */
+	apply_font_size(this, BASE_FONT_SIZE, text_w_out, text_h_out);
+	if (*text_w_out <= this->max_w && *text_h_out <= this->max_h)
+		return;
+
+	/* Too large? Then estimate largest smaller size that would fit */
+	scale_x = (double)this->max_w / (double)*text_w_out;
+	scale_y = (double)this->max_h / (double)*text_h_out;
+	scale = MIN(scale_x, scale_y);
+	scale = MIN(scale, 1) * BASE_FONT_SIZE;
+	size = (int)scale;
+	size = MAX(size, 1);
+
+	/* Check and decrease by one until it fits */
+	for (; size > 1; size--) {
+		apply_font_size(this, size, text_w_out, text_h_out);
+		if (*text_w_out <= this->max_w && *text_h_out <= this->max_h) {
+			ok_size = size;
+			break;
+		}
+	}
+
+	/* Maybe it was too small, then try larger */
+	if (*text_w_out < this->max_w && *text_h_out < this->max_h) {
+		goto start;
+		do {
+			ok_size++;
+		start:
+			if (ok_size == BASE_FONT_SIZE)
+				break;
+			apply_font_size(this, ok_size + 1, text_w_out, text_h_out);
+		} while (*text_w_out < this->max_w && *text_h_out < this->max_h);
+	}
+
+	/* Use the on that fit, 1 if none fit */
+	if (ok_size != size)
+		apply_font_size(this, ok_size, text_w_out, text_h_out);
+}
+
+
+static int
 gcmap_char_table_expose(GtkWidget *widget, GdkEventExpose *event)
 {
-	cairo_t *cr = gdk_cairo_create(widget->window);
+	CharTable *this = (CharTable *)widget;
+	GdkRectangle area = event->area;
+	int r0 = MAX(area.y * this->nrows / widget->allocation.height, 0);
+	int c0 = MAX(area.x * this->ncols / widget->allocation.width,  0);
+	int r1 = MIN((area.y + area.height - 1) * this->nrows / widget->allocation.height + 1, this->nrows);
+	int c1 = MIN((area.x + area.width  - 1) * this->ncols / widget->allocation.width  + 1, this->ncols);
+	GtkStyle *style = gtk_widget_get_style(widget);
+	cairo_t *g;
+	char text[16];
+	int r, c, x0, x1, y0, y1;
+	int text_w, text_h;
+	size_t index, index1;
+	gunichar ch;
+
+	g = gdk_cairo_create(widget->window);
+	if (!g)
+		eprintf("gdk_cairo_create:");
+
+	/* Configure drawing area */
+	gdk_cairo_rectangle(g, &area);
+	cairo_clip(g);
+
+	/* Draw background */
+	set_source_colour(g, &style->base[GTK_STATE_NORMAL]);
+	cairo_paint(g);
 
-	(void) event;
+	/* Draw grid lines */
+	set_source_colour_blend(g, &style->text[GTK_STATE_NORMAL], 0.5, &style->base[GTK_STATE_NORMAL]);
+	cairo_set_line_width(g, 1.0);
+	/* horizontal */
+	y0 = widget->allocation.height * (r0 + 1) / this->nrows;
+	x0 = widget->allocation.width * c0 / this->ncols;
+	x1 = widget->allocation.width * c1 / this->ncols;
+	for (r = r0 + 1; r < r1; r++, y0 = y1) {
+		y1 = widget->allocation.height * (r + 1) / this->nrows;
+		cairo_move_to(g, x0, y0 + 0.5);
+		cairo_line_to(g, x1, y0 + 0.5);
+		cairo_stroke(g);
+	}
+	/* vertical */
+	x0 = widget->allocation.width * (c0 + 1) / this->ncols;
+	y0 = widget->allocation.height * r0 / this->nrows;
+	y1 = widget->allocation.height * r1 / this->nrows;
+	for (c = c0 + 1; c < c1; c++, x0 = x1) {
+		x1 = widget->allocation.width * (c + 1) / this->ncols;
+		cairo_move_to(g, x0 + 0.5, y0);
+		cairo_line_to(g, x0 + 0.5, y1);
+		cairo_stroke(g);
+	}
 
-	cairo_set_source_rgb(cr, 0.2f, 0.2f, 0.2f);
-	cairo_paint(cr);
+	/* Draw gryphs */
+	set_source_colour(g, &style->text[GTK_STATE_NORMAL]);
+	index = (size_t)r0 * (size_t)this->ncols + (size_t)c0;
+	y0 = widget->allocation.height * r0 / this->nrows;
+	for (r = r0; r < r1; r++, y0 = y1, index = index1) {
+		index1 = index + (size_t)this->ncols;
+		x0 = widget->allocation.width * c0 / this->ncols;
+		y1 = widget->allocation.height * (r + 1) / this->nrows;
+		for (c = c0; c < c1; c++, index++, x0 = x1) {
+			ch = FIRST_CHARACTER + (gunichar)index;
+			if (ch > LAST_CHARACTER)
+				goto out;
+			x1 = widget->allocation.width * (c + 1) / this->ncols;
 
-	cairo_set_source_rgb(cr, 1.0f, 1.0f, 1.0f);
-	cairo_move_to(cr, 10, 20);
-	cairo_show_text(cr, "Hello GTK+ 2");
+			format_character(ch, text);
+			fit_text(this, text, &text_w, &text_h);
+			cairo_move_to(g, (x0 + x1 - text_w) / 2, (y0 + y1 - text_h) / 2);
+			pango_cairo_show_layout(g, this->layout);
+		}
+	}
 
-	cairo_destroy(cr);
-	return FALSE;
+out:
+	cairo_destroy(g);
+	return 0;
 }
 
+
 static void
-gcmap_char_table_init(CharTable *self)
+gcmap_char_table_size_allocate(GtkWidget *widget, GtkAllocation *allocation)
 {
-	gtk_widget_set_size_request(GTK_WIDGET(self), 200, 100);
+	CharTable *this = (CharTable *)widget;
+	int text_w, text_h;
+	int cell_w, cell_h;
+
+	GTK_WIDGET_CLASS(gcmap_char_table_parent_class)->size_allocate(widget, allocation);
+
+	pango_layout_set_text(this->layout, REFERENCE_CHARACTER, -1);
+	apply_font_size(this, BASE_FONT_SIZE, &text_w, &text_h);
+	cell_w = MAX(text_w, 1) * CELL_WIDTH_FACTOR;
+	cell_h = MAX(text_h, 1) * CELL_HEIGHT_FACTOR;
+	this->ncols = MAX(widget->allocation.width  / cell_w, 1);
+	this->nrows = MAX(widget->allocation.height / cell_h, 1);
+	cell_w = widget->allocation.width  / this->ncols - 1;
+	cell_h = widget->allocation.height / this->nrows - 1;
+	this->max_w = cell_w - CELL_X_CLEARANCE * 2;
+	this->max_h = cell_h - CELL_Y_CLEARANCE * 2;
+	this->max_w = this->max_w < 1 ? cell_w : this->max_w;
+	this->max_h = this->max_h < 1 ? cell_h : this->max_h;
+}
+
+
+static void
+gcmap_char_table_init(CharTable *this)
+{
+	this->nrows = 1; /* will be set by gcmap_char_table_size_allocate */
+	this->ncols = 1; /* will be set by gcmap_char_table_size_allocate */
+
+	this->font = pango_font_description_new();
+	if (!this->font)
+		eprintf("pango_font_description_new:");
+	pango_font_description_set_family(this->font, BASE_FONT_FAMILY);
+	pango_font_description_set_size(this->font, BASE_FONT_SIZE * PANGO_SCALE);
+	pango_font_description_set_weight(this->font, PANGO_WEIGHT_NORMAL);
+
+	this->layout = gtk_widget_create_pango_layout((GtkWidget *)this, "");
+	if (!this->layout)
+		eprintf("gtk_widget_create_pango_layout:");
+
+	/* TODO on tear down: pango_font_description_free(this->font); */
+	/* TODO on tear down: g_object_unref(this->layout); */
 }
 
 
 static void
-gcmap_char_table_class_init(CharTableClass *klass)
+gcmap_char_table_class_init(CharTableClass *class)
 {
-	GtkWidgetClass *widget_class = GTK_WIDGET_CLASS(klass);
-	widget_class->expose_event = gcmap_char_table_expose;
+	GtkWidgetClass *widget_class = GTK_WIDGET_CLASS(class);
+	widget_class->expose_event = &gcmap_char_table_expose;
+	widget_class->size_allocate = &gcmap_char_table_size_allocate;
 }