path: root/libnautilus-extensions/nautilus-gdk-extensions.c

/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*- */

/* nautilus-gdk-extensions.c: Graphics routines to augment what's in gdk.

   Copyright (C) 1999, 2000 Eazel, Inc.

   The Gnome Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The Gnome Library 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the Gnome Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.

   Authors: Darin Adler <darin@eazel.com>, 
            Pavel Cisler <pavel@eazel.com>,
            Ramiro Estrugo <ramiro@eazel.com>
*/

#include <stdlib.h>

#include <config.h>
#include "nautilus-gdk-extensions.h"
#include <gdk-pixbuf/gdk-pixbuf.h>
#include <gdk/gdkx.h>
#include <gdk/gdkprivate.h>
#include "nautilus-glib-extensions.h"
#include "nautilus-lib-self-check-functions.h"
#include "nautilus-string.h"

#define GRADIENT_BAND_SIZE 4

/**
 * nautilus_fill_rectangle:
 * @drawable: Target to draw into.
 * @gc: Graphics context (mainly for clip).
 * @rectangle: Rectangle to fill.
 *
 * Fill the rectangle with the foreground color.
 * Convenient when you have a GdkRectangle structure.
 */
void
nautilus_fill_rectangle (GdkDrawable *drawable,
			 GdkGC *gc,
			 const GdkRectangle *rectangle)
{
	gdk_draw_rectangle (drawable, gc, TRUE,
			    rectangle->x, rectangle->y,
			    rectangle->width, rectangle->height);
}

/**
 * nautilus_fill_rectangle_with_color:
 * @drawable: Target to draw into.
 * @gc: Graphics context (mainly for clip).
 * @rectangle: Rectangle to fill.
 * @color: Color to fill with.
 *
 * Fill the rectangle with a color.
 * Convenient when you have a GdkRectangle structure.
 */
void
nautilus_fill_rectangle_with_color (GdkDrawable *drawable,
				    GdkGC *gc,
				    const GdkRectangle *rectangle,
				    guint32 rgb)
{
	GdkGCValues saved_values;
	
	/* FIXME bugzilla.eazel.com 1287: Workaround for a bug in gdk_rgb. */
	gdk_rgb_init ();
	
	gdk_gc_get_values (gc, &saved_values);
	gdk_rgb_gc_set_foreground (gc, rgb);
	nautilus_fill_rectangle (drawable, gc, rectangle);
	gdk_gc_set_foreground (gc, &saved_values.foreground);
}

/**
 * nautilus_fill_rectangle_with_gradient:
 * @drawable: Target to draw into.
 * @gc: Graphics context (mainly for clip).
 * @rectangle: Rectangle to draw gradient in.
 * @start_color: Color for the left or top; pixel value does not matter.
 * @end_color: Color for the right or bottom; pixel value does not matter.
 * @horizontal: TRUE if the color changes from left to right. FALSE if from top to bottom.
 *
 * Fill the rectangle with a gradient.
 * The color changes from start_color to end_color.
 * This effect works best on true color displays.
 */
void
nautilus_fill_rectangle_with_gradient (GdkDrawable *drawable,
				       GdkGC *gc,
				       const GdkRectangle *rectangle,
				       guint32 start_rgb,
				       guint32 end_rgb,
				       gboolean horizontal)
{
	GdkRectangle band_box;
	gint16 *position;
	guint16 *size;
	gint num_bands;
	guint16 last_band_size;
	gdouble multiplier;
	gint band;
	guint32 band_rgb;

	g_return_if_fail (drawable != NULL);
	g_return_if_fail (gc != NULL);
	g_return_if_fail (rectangle != NULL);
	g_return_if_fail (horizontal == FALSE || horizontal == TRUE);

	/* Set up the band box so we can access it the same way for horizontal or vertical. */
	band_box = *rectangle;
	position = horizontal ? &band_box.x : &band_box.y;
	size = horizontal ? &band_box.width : &band_box.height;

	/* Figure out how many bands we will need. */
	num_bands = (*size + GRADIENT_BAND_SIZE - 1) / GRADIENT_BAND_SIZE;
	last_band_size = GRADIENT_BAND_SIZE - (GRADIENT_BAND_SIZE * num_bands - *size);

	/* Change the band box to be the size of a single band. */
	*size = GRADIENT_BAND_SIZE;

	/* Set up a multiplier to use to interpolate the colors as we go. */
	multiplier = num_bands <= 1 ? 0.0 : 1.0 / (num_bands - 1);
	
	/* Fill each band with a separate nautilus_draw_rectangle call. */
	for (band = 0; band < num_bands; band++) {
		/* Compute a new color value for each band. */
		band_rgb = nautilus_interpolate_color (band * multiplier, start_rgb, end_rgb);

		/* Last band may need to be a bit smaller to avoid writing outside the box.
		 * This is more efficient than changing and restoring the clip.
		 */
		if (band == num_bands - 1) {
			*size = last_band_size;
		}
		
		nautilus_fill_rectangle_with_color (drawable, gc, &band_box, band_rgb);
		*position += *size;
	}
}

/**
 * nautilus_rectangle_contains:
 * @rectangle: Rectangle possibly containing a point.
 * @x: X coordinate of a point.
 * @y: Y coordinate of a point.
 *
 * Retun TRUE if point is contained inside a rectangle
 */
gboolean
nautilus_rectangle_contains (const GdkRectangle *rectangle, 
			     int x, 
			     int y)
{
	g_return_val_if_fail (rectangle != NULL, FALSE);
	return rectangle->x <= x && rectangle->x + rectangle->width >= x
		&& rectangle->y <= y && rectangle->y + rectangle->height >= y;
}

/**
 * nautilus_rectangle_inset:
 * @rectangle: Rectangle we are insetting.
 * @x: Horizontal ammount to inset by.
 * @y: Vertical ammount to inset by.
 *
 * Inset a rectangle by a given horizontal and vertical ammount.
 * Pass in negative inset values to grow the rectangle, positive to
 * shrink it.
 */
void
nautilus_rectangle_inset (GdkRectangle *rectangle, 
			  int x, 
			  int y)
{
	g_return_if_fail (rectangle != NULL);

	rectangle->x += x;
	rectangle->width -= 2 * x;
	rectangle->y += y;
	rectangle->height -= 2 * y;
}

/**
 * nautilus_interpolate_color:
 * @ratio: Place on line between colors to interpolate.
 * @start_color: Color for one end.
 * @end_color: Color for the other end
 * @interpolated_color: Result.
 *
 * Compute a color between @start_color and @end_color in color space.
 * Currently, the color space used is RGB, but a future version could
 * instead do the interpolation in the best color space for expressing
 * human perception.
 */
guint32
nautilus_interpolate_color (gdouble ratio,
			    guint32 start_rgb,
			    guint32 end_rgb)
{
	guchar red, green, blue;

	g_return_val_if_fail (ratio >= 0.0, 0);
	g_return_val_if_fail (ratio <= 1.0, 0);

	red = ((start_rgb >> 16) & 0xFF) * (1.0 - ratio) + ((end_rgb >> 16) & 0xFF) * ratio;
	green = ((start_rgb >> 8) & 0xFF) * (1.0 - ratio) + ((end_rgb >> 8) & 0xFF) * ratio;
	blue = (start_rgb & 0xFF) * (1.0 - ratio) + (end_rgb & 0xFF) * ratio;
	return (((red << 8) | green) << 8) | blue;
}

/**
 * nautilus_gradient_new
 * @start_color: Color for the top or left.
 * @end_color: Color for the bottom or right.
 * @is_horizontal: Direction of the gradient.
 *
 * Create a string that combines the start and end colors along
 * with the direction of the gradient in a standard format.
 */
char *
nautilus_gradient_new (const char *start_color,
		       const char *end_color,
		       gboolean is_horizontal)
{
	g_return_val_if_fail (is_horizontal == FALSE || is_horizontal == TRUE, NULL);

	/* Handle the special case where the start and end colors are identical.
	   Handle the special case where the end color is an empty string.
	*/
	if (nautilus_strcmp(start_color, end_color) == 0 || end_color == NULL || end_color[0] == '\0') {
		return g_strdup (start_color);
	}

	/* Handle the special case where the start color is an empty string. */
	if (start_color == NULL || start_color[0] == '\0') {
		return g_strdup (end_color);
	}
	
	/* Handle the general case. */
	return g_strconcat (start_color, "-", end_color, is_horizontal ? ":h" : NULL, NULL);
}

/**
 * nautilus_gradient_is_gradient
 * @gradient_spec: A gradient spec. string.
 *
 * Return true if the spec. specifies a gradient instead of a solid color.
 */
gboolean
nautilus_gradient_is_gradient (const char *gradient_spec)
{
	return nautilus_strchr (gradient_spec, '-') != NULL;
}

/**
 * nautilus_gradient_is_horizontal
 * @gradient_spec: A gradient spec. string.
 *
 * Return true if the spec. specifies a horizontal gradient.
 */
gboolean
nautilus_gradient_is_horizontal (const char *gradient_spec)
{
	size_t length;

	length = nautilus_strlen (gradient_spec);
	return length >= 2 && gradient_spec[length - 2] == ':' && gradient_spec[length - 1] == 'h';
}

static char *
nautilus_gradient_strip_trailing_direction_if_any (const char *gradient_spec)
{
	size_t length;

	length = nautilus_strlen (gradient_spec);
	if (length >= 2 && gradient_spec[length - 2] == ':'
	    && (gradient_spec[length - 1] == 'v' || gradient_spec[length - 1] == 'h')) {
		length -= 2;
	}

	return g_strndup (gradient_spec, length);
}

/* For parsing n-point gradients. Successive calls should pass the next_spec value
 * set by the previous call as their first argument - to continue parsing where the
 * previous call left off.
 */
char *
nautilus_gradient_parse_one_color_spec (const char *spec, int *percent, const char **next_spec)
{
	char *result;
	const char *rgb_end_ptr;
	const char *percent_ptr;
	const char *separator_ptr;
	
	percent_ptr   = nautilus_strchr (spec, '%');
	separator_ptr = nautilus_strchr (spec, '-');

	if (percent_ptr != NULL && (separator_ptr == NULL || percent_ptr < separator_ptr)) {
		if (percent != NULL) {
			*percent = (int) strtol (percent_ptr + 1, NULL, 10);
		}
		rgb_end_ptr = percent_ptr;
	} else {
		if (percent != NULL) {
			*percent = 100;
		}
		rgb_end_ptr = separator_ptr;
	}
		
	if (rgb_end_ptr != NULL) {
		result = g_strndup (spec, rgb_end_ptr - spec);
	} else {
		result = nautilus_gradient_strip_trailing_direction_if_any (spec);
	}

	/* It's important not to use spec after setting *next_spec because it's
	 * likely that *next_spec == spec. 
	 */
	if (next_spec != NULL) {
		*next_spec = (separator_ptr != NULL) ? separator_ptr + 1 : NULL;
	}

	return result;
}

/* FIXME anyone using nautilus_gradient_get_start_color_spec or
 * nautilus_gradient_get_end_color_spec is assuming the gradient
 * is 2 colors which is questionable.
 * 
 * Callers should be rewritten and these fns eliminated.
 */
 
/**
 * nautilus_gradient_get_start_color_spec
 * @gradient_spec: A gradient spec. string.
 *
 * Return the start color.
 * This may be the entire gradient_spec if it's a solid color.
 */
char *
nautilus_gradient_get_start_color_spec (const char *gradient_spec)
{
	return nautilus_gradient_parse_one_color_spec (gradient_spec, NULL, NULL);
}

/**
 * nautilus_gradient_get_end_color_spec
 * @gradient_spec: A gradient spec. string.
 *
 * Return the end color.
 * This may be the entire gradient_spec if it's a solid color.
 */
char *
nautilus_gradient_get_end_color_spec (const char *gradient_spec)
{
	char* color = NULL;

	do {
		g_free (color);
		color = nautilus_gradient_parse_one_color_spec (gradient_spec, NULL, &gradient_spec);
	} while (gradient_spec != NULL);

	return color;
}

/* Do the work shared by all the set_color_spec functions below. */
static char *
nautilus_gradient_set_edge_color (const char *gradient_spec,
				  const char *edge_color,
				  gboolean is_horizontal,
				  gboolean change_end)
{
	char *opposite_color;
	char *result;

	g_return_val_if_fail (edge_color != NULL, g_strdup (gradient_spec));

	/* Get the color from the existing gradient spec. for the opposite
	   edge. This will parse away all the stuff we don't want from the
	   old gradient spec.
	*/
	opposite_color = change_end
		? nautilus_gradient_get_start_color_spec (gradient_spec)
		: nautilus_gradient_get_end_color_spec (gradient_spec);

	/* Create a new gradient spec. The nautilus_gradient_new function handles
	   some special cases, so we don't have to bother with them here.
	*/
	result = nautilus_gradient_new (change_end ? opposite_color : edge_color,
					change_end ? edge_color : opposite_color,
					is_horizontal);

	g_free (opposite_color);

	return result;
}

/**
 * nautilus_gradient_set_left_color_spec
 * @gradient_spec: A gradient spec. string.
 * @left_color: Color spec. to replace left color with.
 *
 * Changes the left color to what's passed in.
 * This creates a horizontal gradient.
 */
char *
nautilus_gradient_set_left_color_spec (const char *gradient_spec,
				       const char *left_color)
{
	return nautilus_gradient_set_edge_color (gradient_spec, left_color, TRUE, FALSE);
}

/**
 * nautilus_gradient_set_top_color_spec
 * @gradient_spec: A gradient spec. string.
 * @top_color: Color spec. to replace top color with.
 *
 * Changes the top color to what's passed in.
 * This creates a vertical gradient.
 */
char *
nautilus_gradient_set_top_color_spec (const char *gradient_spec,
				      const char *top_color)
{
	return nautilus_gradient_set_edge_color (gradient_spec, top_color, FALSE, FALSE);
}

/**
 * nautilus_gradient_set_right_color_spec
 * @gradient_spec: A gradient spec. string.
 * @right_color: Color spec. to replace right color with.
 *
 * Changes the right color to what's passed in.
 * This creates a horizontal gradient.
 */
char *
nautilus_gradient_set_right_color_spec (const char *gradient_spec,
					const char *right_color)
{
	return nautilus_gradient_set_edge_color (gradient_spec, right_color, TRUE, TRUE);
}

/**
 * nautilus_gradient_set_bottom_color_spec
 * @gradient_spec: A gradient spec. string.
 * @bottom_color: Color spec. to replace bottom color with.
 *
 * Changes the bottom color to what's passed in.
 * This creates a vertical gradient.
 */
char *
nautilus_gradient_set_bottom_color_spec (const char *gradient_spec,
					 const char *bottom_color)
{
	return nautilus_gradient_set_edge_color (gradient_spec, bottom_color, FALSE, TRUE);
}

/**
 * nautilus_gdk_color_parse_with_white_default
 * @color_spec: A color spec.
 * @color: Pointer to place to put resulting color.
 *
 * The same as gdk_color_parse, except sets the color to white if
 * the spec. can't be parsed instead of returning a boolean flag.
 */
void
nautilus_gdk_color_parse_with_white_default (const char *color_spec,
					     GdkColor *color)
{
	if (color_spec == NULL || !gdk_color_parse (color_spec, color)) {
		color->red = 0xFFFF;
		color->green = 0xFFFF;
		color->blue = 0xFFFF;
	}
}

/**
 * nautilus_parse_rgb_with_white_default
 * @color_spec: A color spec.
 * Returns: An rgb value.
 *
 * The same as gdk_color_parse, except sets the color to white if
 * the spec. can't be parsed instead of returning a boolean flag
 * and returns a guint32 rgb value instead of a GdkColor.
 */
guint32
nautilus_parse_rgb_with_white_default (const char *color_spec)
{
	GdkColor color;

	if (color_spec == NULL || !gdk_color_parse (color_spec, &color)) {
		return NAUTILUS_RGB_COLOR_WHITE;
	}
	return ((color.red << 8) & NAUTILUS_RGB_COLOR_RED)
		| (color.green & NAUTILUS_RGB_COLOR_GREEN)
		| ((color.blue >> 8) & NAUTILUS_RGB_COLOR_BLUE);
}

/**
 * nautilus_gdk_color_to_rgb
 * @color: A GdkColor style color.
 * Returns: An rgb value.
 *
 * Converts from a GdkColor stlye color to a gdk_rgb one.
 * Alpha gets set to fully opaque
 */
guint32
nautilus_gdk_color_to_rgb (const GdkColor *color)
{
	guint32 result;

	result = (0xff0000 | (color->red & 0xff00));
	result <<= 8;
	result |= ((color->green & 0xff00) | (color->blue >> 8));

	return result;
}

/**
 * nautilus_gdk_color_to_rgb
 * @color: a gdk_rgb style value.
 *
 * Converts from a gdk_rgb value style to a GdkColor one.
 * The gdk_rgb color alpha channel is ignored.
 * 
 * Return value: a newly allocated GdkColor.
 */
GdkColor *
nautilus_gdk_rgb_to_color (const guint32 color)
{
	GdkColor *result;
	
	result = g_new0 (GdkColor, 1);
	 
	result->red = (color & 0xff0000) >> 16 ;
	result->green = (color & 0xff00);
	result->blue = color << 8;

	return result;
}


static guint32
nautilus_shift_color_component (guchar component, float shift_by)
{
	guint32 result;
	if (shift_by > 1.0) {
		result = component * (2 - shift_by);
	} else {
		result = 0xff - shift_by * (0xff - component);
	}

	return result & 0xff;
}

/**
 * nautilus_rgb_shift_color
 * @color: A color.
 * @shift_by: darken or lighten factor.
 * Returns: An darkened or lightened rgb value.
 *
 * Darkens (@shift_by > 1) or lightens (@shift_by < 1)
 * @color.
 */
guint32
nautilus_rgb_shift_color (guint32 color, float shift_by)
{
	guint32 result;

	/* shift red by shift_by */
	result = nautilus_shift_color_component((color & 0x00ff0000) >> 16, shift_by);
	result <<= 8;
	/* shift green by shift_by */
	result |=  nautilus_shift_color_component((color & 0x0000ff00) >> 8, shift_by);
	result <<= 8;
	/* shift blue by shift_by */
	result |=  nautilus_shift_color_component((color & 0x000000ff), shift_by);

	/* alpha doesn't change */
	result |= (0xff000000 & color);

	return result;
}

/**
 * nautilus_gdk_font_equal
 * @font_a_null_allowed: A font or NULL.
 * @font_b_null_allowed: A font or NULL.
 *
 * Calls gdk_font_equal, unless one of the fonts is NULL.
 */
gboolean
nautilus_gdk_font_equal (GdkFont *font_a_null_allowed,
			 GdkFont *font_b_null_allowed)
{
	if (font_a_null_allowed == NULL) {
		return font_b_null_allowed == NULL;
	}
	if (font_b_null_allowed == NULL) {
		return FALSE;
	}
	return gdk_font_equal (font_a_null_allowed, font_b_null_allowed);
}

GdkFont *
nautilus_get_largest_fitting_font (const char *text_to_format, int width, const char *font_template)
{
	int font_index, this_width;
	char *font_name;
	/*const int font_sizes[5] = { 28, 24, 18, 14, 12 };*/
	const int font_sizes[4] = { 20, 18, 14, 12 };
	GdkFont *candidate_font;
	char *alt_text_to_format = NULL;
	char *temp_str;
	char *cr_pos;

	temp_str = g_strdup (text_to_format == NULL ? "" : text_to_format);
	cr_pos = strchr (temp_str, '\n');
	if (cr_pos != NULL) {
		*cr_pos = '\0';
		alt_text_to_format = cr_pos + 1;
	}
	
	candidate_font = NULL;
	for (font_index = 0; font_index < NAUTILUS_N_ELEMENTS (font_sizes); font_index++) {
		if (candidate_font != NULL) {
			gdk_font_unref (candidate_font);
		}
		
		font_name = g_strdup_printf (font_template, font_sizes[font_index]);
		candidate_font = gdk_font_load (font_name);
		g_free (font_name);

		if (candidate_font != NULL) {
			this_width = gdk_string_width (candidate_font, temp_str);
			if (alt_text_to_format != NULL) {
				int alt_width = gdk_string_width (candidate_font, alt_text_to_format);
				if (this_width <= width && alt_width <= width) {
					break;
				}
			} else {
				if (this_width <= width) {
					break;
				}
			}
		}
	}
	
	g_free (temp_str);
	return candidate_font;
}

/**
 * nautilus_stipple_bitmap:
 * 
 * Get pointer to singleton 50% stippled bitmap.
 * This is a global object; do not free.
 */
GdkBitmap *
nautilus_stipple_bitmap ()
{
	static GdkBitmap *stipple = NULL;

	if (stipple == NULL) {
		char stipple_bits[] = { 0x02, 0x01 };
		stipple = gdk_bitmap_create_from_data (NULL, stipple_bits, 2, 2);	
	}

	return stipple;
}

/**
 * nautilus_gdk_window_bring_to_front:
 * 
 * Raise window and give it focus.
 */
void 
nautilus_gdk_window_bring_to_front (GdkWindow *window)
{
	gdk_window_raise (window);

	gdk_error_trap_push ();
	XSetInputFocus (GDK_DISPLAY (),
	 	GDK_WINDOW_XWINDOW (window),
	    	RevertToPointerRoot,
	     	GDK_CURRENT_TIME);
	gdk_flush();
	gdk_error_trap_pop ();
}

void
nautilus_set_mini_icon (GdkWindow *window,
			GdkPixmap *pixmap,
			GdkBitmap *mask)
{
        GdkAtom icon_atom;
        long data[2];
 
        g_return_if_fail (window != NULL);
        g_return_if_fail (pixmap != NULL);

        data[0] = GDK_WINDOW_XWINDOW (pixmap);
        if (mask) {
                data[1] = GDK_WINDOW_XWINDOW (mask);
        } else {
                data[1] = 0;
	}

        icon_atom = gdk_atom_intern ("KWM_WIN_ICON", FALSE);
        gdk_property_change (window, icon_atom, icon_atom, 
                             32, GDK_PROP_MODE_REPLACE,
                             (guchar *) data, 2);
}

/**
 * nautilus_gdk_font_get_bold
 * @plain_font: A font.
 * Returns: A bold variant of @plain_font or NULL.
 *
 * Tries to find a bold flavor of a given font. Returns NULL if none is available.
 */
GdkFont *
nautilus_gdk_font_get_bold (const GdkFont *plain_font)
{
	const char *plain_name;
	const char *scanner;
	char *bold_name;
	int count;
	GSList *p;
	GdkFont *result;
	GdkFontPrivate *private_plain;

	private_plain = (GdkFontPrivate *)plain_font;

	if (private_plain->names == NULL) {
		return NULL;
	}


	/* -foundry-family-weight-slant-sel_width-add-style-pixels-points-hor_res-ver_res-spacing-average_width-char_set_registry-char_set_encoding */

	bold_name = NULL;
	for (p = private_plain->names; p != NULL; p = p->next) {
		plain_name = (const char *)p->data;
		scanner = plain_name;

		/* skip past foundry and family to weight */
		for (count = 2; count > 0; count--) {
			scanner = strchr (scanner + 1, '-');
			if (!scanner) {
				break;
			}
		}

		if (!scanner) {
			/* try the other names in the list */
			continue;
		}
		g_assert (*scanner == '-');

		/* copy "-foundry-family-" over */
		scanner++;
		bold_name = g_strndup (plain_name, scanner - plain_name);

		/* skip weight */
		scanner = strchr (scanner, '-');
		g_assert (scanner != NULL);

		/* FIXME bugzilla.eazel.com 2558:
		 * some fonts have demibold, etc. instead. We should be able to figure out
		 * which they are and use them here.
		 */

		/* add "bold" and copy everything past weight over */
		bold_name = g_strconcat (bold_name, "bold", scanner, NULL);
		break;
	}
	
	if (bold_name == NULL) {
		return NULL;
	}
	
	result = gdk_font_load (bold_name);
	g_free (bold_name);

	return result;
}

GdkGC *
nautilus_gdk_create_copy_area_gc (GdkWindow	*window)
{
	GdkGC *copy_area_gc;
	
	g_return_val_if_fail (window != NULL, NULL);

	copy_area_gc = gdk_gc_new (window);

	gdk_gc_set_function (copy_area_gc, GDK_COPY);

	return copy_area_gc;
}

void
nautilus_gdk_gc_ref_if_not_null (GdkGC *gc_or_null)
{
	if (gc_or_null != NULL) {
		gdk_gc_ref (gc_or_null);
	}
}

void
nautilus_gdk_gc_unref_if_not_null (GdkGC *gc_or_null)
{
	if (gc_or_null != NULL) {
		gdk_gc_unref (gc_or_null);
	}
}

#if ! defined (NAUTILUS_OMIT_SELF_CHECK)

static char *
nautilus_gdk_color_as_hex_string (GdkColor color)
{
	return g_strdup_printf("rgb:%04hX/%04hX/%04hX",
			       color.red, color.green, color.blue);
}

static char *
nautilus_self_check_parse (const char *color_spec)
{
	GdkColor color;

	nautilus_gdk_color_parse_with_white_default (color_spec, &color);
	return nautilus_gdk_color_as_hex_string (color);
}

void
nautilus_self_check_gdk_extensions (void)
{
	/* nautilus_interpolate_color */
	NAUTILUS_CHECK_INTEGER_RESULT (nautilus_interpolate_color (0.0, 0, 0), 0);
	NAUTILUS_CHECK_INTEGER_RESULT (nautilus_interpolate_color (0.0, 0, 0xFFFFFF), 0);
	NAUTILUS_CHECK_INTEGER_RESULT (nautilus_interpolate_color (0.5, 0, 0xFFFFFF), 0x7F7F7F);
	NAUTILUS_CHECK_INTEGER_RESULT (nautilus_interpolate_color (1.0, 0, 0xFFFFFF), 0xFFFFFF);

	/* nautilus_fill_rectangle */
	/* Make a GdkImage and fill it, maybe? */

	/* nautilus_fill_rectangle_with_color */

	/* nautilus_fill_rectangle_with_gradient */

	/* nautilus_gradient_new */
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_new ("", "", FALSE), "");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_new ("a", "b", FALSE), "a-b");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_new ("a", "b", TRUE), "a-b:h");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_new ("a", "a", FALSE), "a");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_new ("a", "a", TRUE), "a");

	/* nautilus_gradient_is_gradient */
	NAUTILUS_CHECK_BOOLEAN_RESULT (nautilus_gradient_is_gradient (""), FALSE);
	NAUTILUS_CHECK_BOOLEAN_RESULT (nautilus_gradient_is_gradient ("-"), TRUE);
	NAUTILUS_CHECK_BOOLEAN_RESULT (nautilus_gradient_is_gradient ("a"), FALSE);
	NAUTILUS_CHECK_BOOLEAN_RESULT (nautilus_gradient_is_gradient ("a-b"), TRUE);
	NAUTILUS_CHECK_BOOLEAN_RESULT (nautilus_gradient_is_gradient ("a-b:h"), TRUE);

	/* nautilus_gradient_get_start_color_spec */
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_get_start_color_spec (""), "");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_get_start_color_spec ("-"), "");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_get_start_color_spec ("a"), "a");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_get_start_color_spec ("a-b"), "a");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_get_start_color_spec ("a-"), "a");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_get_start_color_spec ("-b"), "");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_get_start_color_spec ("a:h"), "a");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_get_start_color_spec ("a:v"), "a");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_get_start_color_spec ("a:c"), "a:c");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_get_start_color_spec ("a:-b"), "a:");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_get_start_color_spec ("a:-b:v"), "a:");

	/* nautilus_gradient_get_end_color_spec */
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_get_end_color_spec (""), "");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_get_end_color_spec ("-"), "");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_get_end_color_spec ("a"), "a");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_get_end_color_spec ("a-b"), "b");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_get_end_color_spec ("a-"), "");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_get_end_color_spec ("-b"), "b");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_get_end_color_spec ("a:h"), "a");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_get_end_color_spec ("a:v"), "a");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_get_end_color_spec ("a:c"), "a:c");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_get_end_color_spec ("a:-b"), "b");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_get_end_color_spec ("a:-b:v"), "b");

	/* nautilus_gradient_set_left_color_spec */
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_left_color_spec ("", ""), "");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_left_color_spec ("", "a"), "a");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_left_color_spec ("a", ""), "a");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_left_color_spec ("a", "a"), "a");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_left_color_spec ("a", "b"), "b-a:h");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_left_color_spec ("a-c:v", "b"), "b-c:h");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_left_color_spec ("a-c:v", "c"), "c");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_left_color_spec ("a:-b:v", "d"), "d-b:h");

	/* nautilus_gradient_set_top_color_spec */
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_top_color_spec ("", ""), "");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_top_color_spec ("", "a"), "a");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_top_color_spec ("a", ""), "a");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_top_color_spec ("a", "a"), "a");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_top_color_spec ("a", "b"), "b-a");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_top_color_spec ("a-c:v", "b"), "b-c");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_top_color_spec ("a-c:v", "c"), "c");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_top_color_spec ("a:-b:h", "d"), "d-b");

	/* nautilus_gradient_set_right_color_spec */
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_right_color_spec ("", ""), "");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_right_color_spec ("", "a"), "a");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_right_color_spec ("a", ""), "a");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_right_color_spec ("a", "a"), "a");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_right_color_spec ("a", "b"), "a-b:h");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_right_color_spec ("a-c:v", "b"), "a-b:h");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_right_color_spec ("a-c:v", "c"), "a-c:h");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_right_color_spec ("a:-b:v", "d"), "a:-d:h");

	/* nautilus_gradient_set_bottom_color_spec */
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_bottom_color_spec ("", ""), "");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_bottom_color_spec ("", "a"), "a");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_bottom_color_spec ("a", ""), "a");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_bottom_color_spec ("a", "a"), "a");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_bottom_color_spec ("a", "b"), "a-b");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_bottom_color_spec ("a-c:v", "b"), "a-b");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_bottom_color_spec ("a-c:v", "c"), "a-c");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_gradient_set_bottom_color_spec ("a:-b:h", "d"), "a:-d");

	/* nautilus_gdk_color_parse_with_white_default */
	NAUTILUS_CHECK_STRING_RESULT (nautilus_self_check_parse (""), "rgb:FFFF/FFFF/FFFF");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_self_check_parse ("a"), "rgb:FFFF/FFFF/FFFF");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_self_check_parse ("white"), "rgb:FFFF/FFFF/FFFF");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_self_check_parse ("black"), "rgb:0000/0000/0000");
	NAUTILUS_CHECK_STRING_RESULT (nautilus_self_check_parse ("rgb:0123/4567/89AB"), "rgb:0123/4567/89AB");
}

#endif /* ! NAUTILUS_OMIT_SELF_CHECK */