Implement basic character table

Signed-off-by: Mattias Andrée <m@maandree.se>

6 files changed, 285 insertions, 17 deletions

diff --git a/Makefile b/Makefile
index 5eb2cab..0725b98 100644
--- a/Makefile
+++ b/Makefile
@@ -5,7 +5,8 @@ include $(CONFIGFILE)
 
 OBJ =\
 	gcmap.o\
-	char-table.o
+	char-table.o\
+	colour.o
 
 HDR =\
 	common.h\
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;
 }
 
 
diff --git a/char-table.h b/char-table.h
index 0097e05..87d65d4 100644
--- a/char-table.h
+++ b/char-table.h
@@ -12,6 +12,9 @@
 
 typedef struct _CharTable {
 	GtkDrawingArea parent_instance;
+	int nrows, ncols, max_w, max_h;
+	PangoFontDescription *font;
+	PangoLayout *layout;
 } CharTable;
 
 typedef struct _CharTableClass {
diff --git a/colour.c b/colour.c
new file mode 100644
index 0000000..8b5c401
--- /dev/null
+++ b/colour.c
@@ -0,0 +1,47 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+double
+srgb_encode_unsigned(double t)
+{
+	return t <= 0.0031306684425217108
+		? 12.92 * t
+		: fma(1.055, pow(t, 1 / 2.4), -0.055);
+}
+
+double
+srgb_decode_unsigned(double t)
+{
+	return t <= 0.0031306684425217108 * 12.92
+		? t / 12.92
+		: pow((t + 0.055) / 1.055, 2.4);
+}
+
+
+double
+srgb_blend(double at0, double t, double at1)
+{
+	at0 = srgb_decode_unsigned(at0);
+	at1 = srgb_decode_unsigned(at1);
+	return srgb_encode_unsigned(fma((1 - t), at0, t * at1));
+}
+
+
+void
+set_source_colour_blend(cairo_t *g, const GdkColor *at0, double t, const GdkColor *at1)
+{
+	double max   = (double)UINT16_MAX;
+	double red   = srgb_blend(at0->red   / max, t, at1->red   / max);
+	double green = srgb_blend(at0->green / max, t, at1->green / max);
+	double blue  = srgb_blend(at0->blue  / max, t, at1->blue  / max);
+	cairo_set_source_rgb(g, red, green, blue);
+}
+
+
+void
+set_source_colour(cairo_t *g, const GdkColor *colour)
+{
+	double max = (double)UINT16_MAX;
+	cairo_set_source_rgb(g, colour->red / max, colour->green / max, colour->blue / max);
+}
diff --git a/common.h b/common.h
index a7cd690..a30d4c7 100644
--- a/common.h
+++ b/common.h
@@ -2,6 +2,10 @@
 #ifndef COMMON_H_
 #define COMMON_H_
 
+#if defined(__GNUC__)
+# pragma GCC diagnostic ignored "-Wunsuffixed-float-constants"
+#endif
+
 #include <libsimple.h>
 #include <libsimple-arg.h>
 #include <libcmap.h>
@@ -15,6 +19,7 @@
 #if defined(__GNUC__)
 # pragma GCC diagnostic pop
 #endif
+#include <math.h>
 
 #if GTK_CHECK_VERSION(2, 12, 0)
 # define HAVE_ITEM_TOOLTIPS
@@ -24,4 +29,11 @@
 
 #include "char-table.h"
 
+/* colour.c */
+double srgb_encode_unsigned(double t);
+double srgb_decode_unsigned(double t);
+double srgb_blend(double at0, double t, double at1);
+void set_source_colour_blend(cairo_t *g, const GdkColor *at0, double t, const GdkColor *at1);
+void set_source_colour(cairo_t *g, const GdkColor *colour);
+
 #endif
diff --git a/config.mk b/config.mk
index ba12191..578c9b5 100644
--- a/config.mk
+++ b/config.mk
@@ -5,7 +5,7 @@ CC = c99
 
 CPPFLAGS = -D_DEFAULT_SOURCE -D_BSD_SOURCE -D_XOPEN_SOURCE=700 -D_GNU_SOURCE
 CFLAGS   = $$(pkg-config --cflags pango)
-LDFLAGS  = -lsimple -lcmap $$(pkg-config --libs pango)
+LDFLAGS  = -lm -lsimple -lcmap $$(pkg-config --libs pango)
 
 CFLAGS_GTK2  = $$(pkg-config --cflags gtk+-2.0)
 LDFLAGS_GTK2 = $$(pkg-config --libs gtk+-2.0)