[gthumb: 4/23] added some utility functions in cairo-utils.[ch]

[Paolo Bacchilega <paobac src gnome org>]

commit 1bdc5c5b288a0bfc4a497986d6fd43296e9a57a5
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Thu Dec 23 23:47:56 2010 +0100

    added some utility functions in cairo-utils.[ch]

 gthumb/Makefile.am   |    2 +
 gthumb/cairo-utils.c |  301 ++++++++++++++++++++++++++++++++++++++++++++++++++
 gthumb/cairo-utils.h |   80 +++++++++++++
 3 files changed, 383 insertions(+), 0 deletions(-)
---
diff --git a/gthumb/Makefile.am b/gthumb/Makefile.am
index e9e385e..695c9f6 100644
--- a/gthumb/Makefile.am
+++ b/gthumb/Makefile.am
@@ -26,6 +26,7 @@ PUBLIC_BUILT_HEADER_FILES =				\
 
 PUBLIC_HEADER_FILES = 					\
 	$(PUBLIC_BUILT_HEADER_FILES)			\
+	cairo-utils.h					\
 	dom.h						\
 	egg-macros.h					\
 	eggfileformatchooser.h				\
@@ -140,6 +141,7 @@ gthumb_SOURCES = 					\
 	$(EXTERNAL)					\
 	$(PUBLIC_HEADER_FILES)				\
 	$(PRIVATE_HEADER_FILES)				\
+	cairo-utils.c					\
 	dlg-extensions.c				\
 	dlg-personalize-filters.c			\
 	dlg-preferences.c				\
diff --git a/gthumb/cairo-utils.c b/gthumb/cairo-utils.c
new file mode 100644
index 0000000..4f6c7f1
--- /dev/null
+++ b/gthumb/cairo-utils.c
@@ -0,0 +1,301 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
+
+/*
+ *  GThumb
+ *
+ *  Copyright (C) 2010 Free Software Foundation, Inc.
+ *
+ *  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 <math.h>
+#include "cairo-utils.h"
+
+
+void
+_gdk_color_to_cairo_color (GdkColor      *g_color,
+			   cairo_color_t *c_color)
+{
+	c_color->r = (double) g_color->red / 65535;
+	c_color->g = (double) g_color->green / 65535;
+	c_color->b = (double) g_color->blue / 65535;
+	c_color->a = 1.0;
+}
+
+
+void
+_gdk_color_to_cairo_color_255 (GdkColor          *g_color,
+			       cairo_color_255_t *c_color)
+{
+	c_color->r = (guchar) 255.0 * g_color->red / 65535.0;
+	c_color->g = (guchar) 255.0 * g_color->green / 65535.0;
+	c_color->b = (guchar) 255.0 * g_color->blue / 65535.0;
+	c_color->a = 0xff;
+}
+
+
+void
+_cairo_paint_full_gradient (cairo_surface_t *surface,
+			    GdkColor        *h_color1,
+			    GdkColor        *h_color2,
+			    GdkColor        *v_color1,
+			    GdkColor        *v_color2)
+{
+	cairo_color_255_t  hcolor1;
+	cairo_color_255_t  hcolor2;
+	cairo_color_255_t  vcolor1;
+	cairo_color_255_t  vcolor2;
+	int                width;
+	int                height;
+	int                s_stride;
+	unsigned char     *s_pixels;
+	int                h, w;
+	double             x, y;
+	double             x_y, x_1_y, y_1_x, _1_x_1_y;
+	guchar             red, green, blue;
+
+	if (cairo_surface_status (surface) != CAIRO_STATUS_SUCCESS)
+		return;
+
+	_gdk_color_to_cairo_color_255 (h_color1, &hcolor1);
+	_gdk_color_to_cairo_color_255 (h_color2, &hcolor2);
+	_gdk_color_to_cairo_color_255 (v_color1, &vcolor1);
+	_gdk_color_to_cairo_color_255 (v_color2, &vcolor2);
+
+	width = cairo_image_surface_get_width (surface);
+	height = cairo_image_surface_get_height (surface);
+	s_stride = cairo_image_surface_get_stride (surface);
+	s_pixels = cairo_image_surface_get_data (surface);
+
+	for (h = 0; h < height; h++) {
+		guchar *s_iter = s_pixels;
+
+	        x = (double) (height - h) / height;
+
+	        for (w = 0; w < width; w++) {
+	        	y = (double) (width - w) / width;
+
+			x_y      = x * y;
+			x_1_y    = x * (1.0 - y);
+			y_1_x    = y * (1.0 - x);
+			_1_x_1_y = (1.0 - x) * (1.0 - y);
+
+			red   = hcolor1.r * x_y + hcolor2.r * x_1_y + vcolor1.r * y_1_x + vcolor2.r * _1_x_1_y;
+			green = hcolor1.g * x_y + hcolor2.g * x_1_y + vcolor1.g * y_1_x + vcolor2.g * _1_x_1_y;
+			blue  = hcolor1.b * x_y + hcolor2.b * x_1_y + vcolor1.b * y_1_x + vcolor2.b * _1_x_1_y;
+
+#if G_BYTE_ORDER == G_LITTLE_ENDIAN
+	        	/* BGRA */
+			s_iter[0] = blue;
+			s_iter[1] = green;
+			s_iter[2] = red;
+			s_iter[3] = 0xff;
+#elif G_BYTE_ORDER == G_BIG_ENDIAN
+			/* ARGB */
+			s_iter[0] = 0xff;
+			s_iter[1] = red;
+			s_iter[2] = green;
+			s_iter[3] = blue;
+#else /* PDP endianness */
+			/* RABG */
+			s_iter[0] = red;
+			s_iter[1] = 0xff;
+			s_iter[2] = blue;
+			s_iter[3] = green;
+#endif
+
+			s_iter += 4;
+		}
+
+		s_pixels += s_stride;
+	}
+}
+
+
+void
+_cairo_draw_rounded_box (cairo_t *cr,
+			 double   x,
+			 double   y,
+			 double   w,
+			 double   h,
+			 double   r)
+{
+	cairo_move_to (cr, x, y + r);
+	if (r > 0)
+		cairo_arc (cr, x + r, y + r, r, 1.0 * M_PI, 1.5 * M_PI);
+	cairo_rel_line_to (cr, w - (r * 2), 0);
+	if (r > 0)
+		cairo_arc (cr, x + w - r, y + r, r, 1.5 * M_PI, 2.0 * M_PI);
+	cairo_rel_line_to (cr, 0, h - (r * 2));
+	if (r > 0)
+		cairo_arc (cr, x + w - r, y + h - r, r, 0.0 * M_PI, 0.5 * M_PI);
+	cairo_rel_line_to (cr, - (w - (r * 2)), 0);
+	if (r > 0)
+		cairo_arc (cr, x + r, y + h - r, r, 0.5 * M_PI, 1.0 * M_PI);
+}
+
+
+void
+_cairo_draw_drop_shadow (cairo_t *cr,
+			 double   x,
+			 double   y,
+			 double   w,
+			 double   h,
+			 double   r)
+{
+	int i;
+
+	cairo_save (cr);
+	cairo_set_line_width (cr, 1);
+	for (i = r; i >= 0; i--) {
+		cairo_set_source_rgba (cr, 0.0, 0.0, 0.0, (0.1 / r)* (r - i + 1));
+		_cairo_draw_rounded_box (cr,
+					 x + r - i,
+					 y + r - i,
+					 w + (i * 2),
+					 h + (i * 2),
+					 r);
+		cairo_fill (cr);
+	}
+	cairo_restore (cr);
+}
+
+
+void
+_cairo_draw_frame (cairo_t *cr,
+		   double   x,
+		   double   y,
+		   double   w,
+		   double   h,
+		   double   r)
+{
+	cairo_save (cr);
+	cairo_set_line_width (cr, r);
+	cairo_rectangle (cr, x - (r / 2), y - (r / 2), w + r, h + r);
+	cairo_stroke (cr);
+	cairo_restore (cr);
+}
+
+
+void
+_cairo_draw_slide (cairo_t  *cr,
+		   double    frame_x,
+		   double    frame_y,
+		   double    frame_width,
+		   double    frame_height,
+		   double    image_width,
+		   double    image_height,
+		   GdkColor *frame_color,
+		   gboolean  draw_inner_border)
+{
+	const double dark_gray = 0.60;
+	const double mid_gray = 0.80;
+	const double darker_gray = 0.45;
+	const double light_gray = 0.99;
+	double       frame_x2;
+	double       frame_y2;
+
+	frame_x += 0.5;
+	frame_y += 0.5;
+
+	frame_x2 = frame_x + frame_width;
+	frame_y2 = frame_y + frame_height;
+
+	cairo_save (cr);
+	cairo_set_antialias (cr, CAIRO_ANTIALIAS_NONE);
+	cairo_set_line_width (cr, 1.0);
+
+	/* background. */
+
+	gdk_cairo_set_source_color (cr, frame_color);
+	cairo_rectangle (cr,
+			 frame_x,
+			 frame_y,
+			 frame_width,
+			 frame_height);
+	cairo_fill (cr);
+
+	if ((image_width > 0) && (image_height > 0)) {
+		double image_x, image_y;
+
+		image_x = frame_x + (frame_width - image_width) / 2 + 0.5;
+		image_y = frame_y + (frame_height - image_height) / 2 + 0.5;
+
+		/* inner border. */
+
+		if (draw_inner_border) {
+			double image_x2, image_y2;
+
+			cairo_set_source_rgb (cr, 1.0, 1.0, 1.0);
+			cairo_rectangle (cr,
+					 image_x,
+					 image_y,
+					 image_width,
+					 image_height);
+			cairo_fill (cr);
+
+			image_x -= 1;
+			image_y -= 1;
+			image_x2 = image_x + image_width + 2;
+			image_y2 = image_y + image_height + 2;
+
+			cairo_set_source_rgb (cr, dark_gray, dark_gray, dark_gray);
+			cairo_move_to (cr, image_x, image_y);
+			cairo_line_to (cr, image_x2 - 1, image_y);
+			cairo_move_to (cr, image_x, image_y);
+			cairo_line_to (cr, image_x, image_y2 - 1);
+			cairo_stroke (cr);
+
+			cairo_set_source_rgb (cr, mid_gray, mid_gray, mid_gray);
+			cairo_move_to (cr, image_x2 - 1, image_y);
+			cairo_line_to (cr, image_x2 - 1, image_y2);
+			cairo_move_to (cr, image_x, image_y2 - 1);
+			cairo_line_to (cr, image_x2, image_y2 - 1);
+			cairo_stroke (cr);
+		}
+	}
+
+	/* outer border. */
+
+	cairo_set_source_rgb (cr, mid_gray, mid_gray, mid_gray);
+	cairo_move_to (cr, frame_x - 1, frame_y);
+	cairo_line_to (cr, frame_x2, frame_y);
+	cairo_move_to (cr, frame_x, frame_y - 1);
+	cairo_line_to (cr, frame_x, frame_y2);
+	cairo_stroke (cr);
+
+	cairo_set_source_rgb (cr, darker_gray, darker_gray, darker_gray);
+	cairo_move_to (cr, frame_x2, frame_y - 1);
+	cairo_line_to (cr, frame_x2, frame_y2);
+	cairo_move_to (cr, frame_x - 1, frame_y2);
+	cairo_line_to (cr, frame_x2, frame_y2);
+	cairo_stroke (cr);
+
+	cairo_set_source_rgb (cr, light_gray, light_gray, light_gray);
+	cairo_move_to (cr, frame_x, frame_y + 1);
+	cairo_line_to (cr, frame_x2 - 1, frame_y + 1);
+	cairo_move_to (cr, frame_x + 1, frame_y);
+	cairo_line_to (cr, frame_x + 1, frame_y2 - 1);
+	cairo_stroke (cr);
+
+	cairo_set_source_rgb (cr, dark_gray, dark_gray, dark_gray);
+	cairo_move_to (cr, frame_x2 - 1, frame_y);
+	cairo_line_to (cr, frame_x2 - 1, frame_y2 - 1);
+	cairo_move_to (cr, frame_x, frame_y2 - 1);
+	cairo_line_to (cr, frame_x2 - 1, frame_y2 - 1);
+	cairo_stroke (cr);
+
+	cairo_restore (cr);
+}
diff --git a/gthumb/cairo-utils.h b/gthumb/cairo-utils.h
new file mode 100644
index 0000000..ace63b7
--- /dev/null
+++ b/gthumb/cairo-utils.h
@@ -0,0 +1,80 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
+
+/*
+ *  GThumb
+ *
+ *  Copyright (C) 2010 Free Software Foundation, Inc.
+ *
+ *  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/>.
+ */
+
+#ifndef CAIRO_UTILS_H
+#define CAIRO_UTILS_H
+
+#include <glib.h>
+#include <gdk/gdk.h>
+#include <cairo.h>
+
+typedef struct {
+	double r;
+	double g;
+	double b;
+	double a;
+} cairo_color_t;
+
+typedef struct {
+	guchar r;
+	guchar g;
+	guchar b;
+	guchar a;
+} cairo_color_255_t;
+
+void         _gdk_color_to_cairo_color          (GdkColor          *g_color,
+			         	 	 cairo_color_t     *c_color);
+void         _gdk_color_to_cairo_color_255      (GdkColor          *g_color,
+			         	 	 cairo_color_255_t *c_color);
+void         _cairo_paint_full_gradient         (cairo_surface_t   *surface,
+				 	 	 GdkColor          *h_color1,
+				 	 	 GdkColor          *h_color2,
+				 	 	 GdkColor          *v_color1,
+				 	 	 GdkColor          *v_color2);
+void         _cairo_draw_rounded_box            (cairo_t           *cr,
+			 	 	 	 double             x,
+			 	 	 	 double             y,
+			 	 	 	 double             w,
+			 	 	 	 double             h,
+			 	 	 	 double             r);
+void         _cairo_draw_drop_shadow            (cairo_t           *cr,
+ 	 	 	 	 	 	 double             x,
+ 	 	 	 	 	 	 double             y,
+ 	 	 	 	 	 	 double             w,
+ 	 	 	 	 	 	 double             h,
+ 	 	 	 	 	 	 double             r);
+void         _cairo_draw_frame                  (cairo_t           *cr,
+ 	 	 	 	 	 	 double             x,
+ 	 	 	 	 	 	 double             y,
+ 	 	 	 	 	 	 double             w,
+ 	 	 	 	 	 	 double             h,
+ 	 	 	 	 	 	 double             r);
+void         _cairo_draw_slide                  (cairo_t           *cr,
+		   	   	   	   	 double             frame_x,
+		   	   	   	   	 double             frame_y,
+		   	   	   	   	 double             frame_width,
+		   	   	   	   	 double             frame_height,
+		   	   	   	   	 double             image_width,
+		   	   	   	   	 double             image_height,
+		   	   	   	   	 GdkColor          *frame_color,
+		   	   	   	   	 gboolean           draw_inner_border);
+
+#endif /* CAIRO_UTILS_H */