gtk/gdk-pixbuf/gdk-pixbuf.c
Matthias Clasen b863097016 Document the "orientation" option.
2007-07-02  Matthias Clasen <mclasen@redhat.com>

        * gdk-pixbuf.c (gdk_pixbuf_get_option): Document the
        "orientation" option.

        * gdk-pixbuf.symbols:
        * gdk-pixbuf-core.h:
        * gdk-pixbuf-util.c (gdk_pixbuf_apply_embedded_orientation):
        New function to handle Exif orientation information in
        tiff and jpeg images.  (#439567, Michael Chudobiak)


svn path=/trunk/; revision=18340
2007-07-02 14:47:45 +00:00

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/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 8 -*- */
/* GdkPixbuf library - Basic memory management
*
* Copyright (C) 1999 The Free Software Foundation
*
* Authors: Mark Crichton <crichton@gimp.org>
* Miguel de Icaza <miguel@gnu.org>
* Federico Mena-Quintero <federico@gimp.org>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include <config.h>
#include <math.h>
#include <stdlib.h>
#include <string.h>
#define GDK_PIXBUF_COMPILATION
#include "gdk-pixbuf.h"
#include "gdk-pixbuf-private.h"
/* Include the marshallers */
#include <glib-object.h>
#include "gdk-pixbuf-marshal.c"
#include "gdk-pixbuf-alias.h"
static void gdk_pixbuf_finalize (GObject *object);
static void gdk_pixbuf_set_property (GObject *object,
guint prop_id,
const GValue *value,
GParamSpec *pspec);
static void gdk_pixbuf_get_property (GObject *object,
guint prop_id,
GValue *value,
GParamSpec *pspec);
enum
{
PROP_0,
PROP_COLORSPACE,
PROP_N_CHANNELS,
PROP_HAS_ALPHA,
PROP_BITS_PER_SAMPLE,
PROP_WIDTH,
PROP_HEIGHT,
PROP_ROWSTRIDE,
PROP_PIXELS
};
G_DEFINE_TYPE (GdkPixbuf, gdk_pixbuf, G_TYPE_OBJECT)
static void
gdk_pixbuf_init (GdkPixbuf *pixbuf)
{
}
static void
gdk_pixbuf_class_init (GdkPixbufClass *klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
object_class->finalize = gdk_pixbuf_finalize;
object_class->set_property = gdk_pixbuf_set_property;
object_class->get_property = gdk_pixbuf_get_property;
#define PIXBUF_PARAM_FLAGS G_PARAM_READWRITE|G_PARAM_CONSTRUCT_ONLY|\
G_PARAM_STATIC_NAME|G_PARAM_STATIC_NICK|G_PARAM_STATIC_BLURB
/**
* GdkPixbuf:n-channels:
*
* The number of samples per pixel.
* Currently, only 3 or 4 samples per pixel are supported.
*/
g_object_class_install_property (object_class,
PROP_N_CHANNELS,
g_param_spec_int ("n-channels",
P_("Number of Channels"),
P_("The number of samples per pixel"),
0,
G_MAXINT,
3,
PIXBUF_PARAM_FLAGS));
g_object_class_install_property (object_class,
PROP_COLORSPACE,
g_param_spec_enum ("colorspace",
P_("Colorspace"),
P_("The colorspace in which the samples are interpreted"),
GDK_TYPE_COLORSPACE,
GDK_COLORSPACE_RGB,
PIXBUF_PARAM_FLAGS));
g_object_class_install_property (object_class,
PROP_HAS_ALPHA,
g_param_spec_boolean ("has-alpha",
P_("Has Alpha"),
P_("Whether the pixbuf has an alpha channel"),
FALSE,
PIXBUF_PARAM_FLAGS));
/**
* GdkPixbuf:bits-per-sample:
*
* The number of bits per sample.
* Currently only 8 bit per sample are supported.
*/
g_object_class_install_property (object_class,
PROP_BITS_PER_SAMPLE,
g_param_spec_int ("bits-per-sample",
P_("Bits per Sample"),
P_("The number of bits per sample"),
1,
16,
8,
PIXBUF_PARAM_FLAGS));
g_object_class_install_property (object_class,
PROP_WIDTH,
g_param_spec_int ("width",
P_("Width"),
P_("The number of columns of the pixbuf"),
1,
G_MAXINT,
1,
PIXBUF_PARAM_FLAGS));
g_object_class_install_property (object_class,
PROP_HEIGHT,
g_param_spec_int ("height",
P_("Height"),
P_("The number of rows of the pixbuf"),
1,
G_MAXINT,
1,
PIXBUF_PARAM_FLAGS));
/**
* GdkPixbuf:rowstride:
*
* The number of bytes between the start of a row and
* the start of the next row. This number must (obviously)
* be at least as large as the width of the pixbuf.
*/
g_object_class_install_property (object_class,
PROP_ROWSTRIDE,
g_param_spec_int ("rowstride",
P_("Rowstride"),
P_("The number of bytes between the start of a row and the start of the next row"),
1,
G_MAXINT,
1,
PIXBUF_PARAM_FLAGS));
g_object_class_install_property (object_class,
PROP_PIXELS,
g_param_spec_pointer ("pixels",
P_("Pixels"),
P_("A pointer to the pixel data of the pixbuf"),
PIXBUF_PARAM_FLAGS));
}
static void
gdk_pixbuf_finalize (GObject *object)
{
GdkPixbuf *pixbuf = GDK_PIXBUF (object);
if (pixbuf->destroy_fn)
(* pixbuf->destroy_fn) (pixbuf->pixels, pixbuf->destroy_fn_data);
G_OBJECT_CLASS (gdk_pixbuf_parent_class)->finalize (object);
}
/**
* gdk_pixbuf_ref:
* @pixbuf: A pixbuf.
*
* Adds a reference to a pixbuf.
*
* Return value: The same as the @pixbuf argument.
*
* Deprecated: Use g_object_ref().
**/
GdkPixbuf *
gdk_pixbuf_ref (GdkPixbuf *pixbuf)
{
return (GdkPixbuf *) g_object_ref (pixbuf);
}
/**
* gdk_pixbuf_unref:
* @pixbuf: A pixbuf.
*
* Removes a reference from a pixbuf.
*
* Deprecated: Use g_object_unref().
**/
void
gdk_pixbuf_unref (GdkPixbuf *pixbuf)
{
g_object_unref (pixbuf);
}
/* Used as the destroy notification function for gdk_pixbuf_new() */
static void
free_buffer (guchar *pixels, gpointer data)
{
g_free (pixels);
}
/**
* gdk_pixbuf_new:
* @colorspace: Color space for image
* @has_alpha: Whether the image should have transparency information
* @bits_per_sample: Number of bits per color sample
* @width: Width of image in pixels, must be > 0
* @height: Height of image in pixels, must be > 0
*
* Creates a new #GdkPixbuf structure and allocates a buffer for it. The
* buffer has an optimal rowstride. Note that the buffer is not cleared;
* you will have to fill it completely yourself.
*
* Return value: A newly-created #GdkPixbuf with a reference count of 1, or
* %NULL if not enough memory could be allocated for the image buffer.
**/
GdkPixbuf *
gdk_pixbuf_new (GdkColorspace colorspace,
gboolean has_alpha,
int bits_per_sample,
int width,
int height)
{
guchar *buf;
int channels;
int rowstride;
gsize bytes;
g_return_val_if_fail (colorspace == GDK_COLORSPACE_RGB, NULL);
g_return_val_if_fail (bits_per_sample == 8, NULL);
g_return_val_if_fail (width > 0, NULL);
g_return_val_if_fail (height > 0, NULL);
channels = has_alpha ? 4 : 3;
rowstride = width * channels;
if (rowstride / channels != width || rowstride + 3 < 0) /* overflow */
return NULL;
/* Always align rows to 32-bit boundaries */
rowstride = (rowstride + 3) & ~3;
bytes = height * rowstride;
if (bytes / rowstride != height) /* overflow */
return NULL;
buf = g_try_malloc (bytes);
if (!buf)
return NULL;
return gdk_pixbuf_new_from_data (buf, colorspace, has_alpha, bits_per_sample,
width, height, rowstride,
free_buffer, NULL);
}
/**
* gdk_pixbuf_copy:
* @pixbuf: A pixbuf.
*
* Creates a new #GdkPixbuf with a copy of the information in the specified
* @pixbuf.
*
* Return value: A newly-created pixbuf with a reference count of 1, or %NULL if
* not enough memory could be allocated.
**/
GdkPixbuf *
gdk_pixbuf_copy (const GdkPixbuf *pixbuf)
{
guchar *buf;
int size;
g_return_val_if_fail (pixbuf != NULL, NULL);
/* Calculate a semi-exact size. Here we copy with full rowstrides;
* maybe we should copy each row individually with the minimum
* rowstride?
*/
size = ((pixbuf->height - 1) * pixbuf->rowstride +
pixbuf->width * ((pixbuf->n_channels * pixbuf->bits_per_sample + 7) / 8));
buf = g_try_malloc (size * sizeof (guchar));
if (!buf)
return NULL;
memcpy (buf, pixbuf->pixels, size);
return gdk_pixbuf_new_from_data (buf,
pixbuf->colorspace, pixbuf->has_alpha,
pixbuf->bits_per_sample,
pixbuf->width, pixbuf->height,
pixbuf->rowstride,
free_buffer,
NULL);
}
/**
* gdk_pixbuf_new_subpixbuf:
* @src_pixbuf: a #GdkPixbuf
* @src_x: X coord in @src_pixbuf
* @src_y: Y coord in @src_pixbuf
* @width: width of region in @src_pixbuf
* @height: height of region in @src_pixbuf
*
* Creates a new pixbuf which represents a sub-region of
* @src_pixbuf. The new pixbuf shares its pixels with the
* original pixbuf, so writing to one affects both.
* The new pixbuf holds a reference to @src_pixbuf, so
* @src_pixbuf will not be finalized until the new pixbuf
* is finalized.
*
* Return value: a new pixbuf
**/
GdkPixbuf*
gdk_pixbuf_new_subpixbuf (GdkPixbuf *src_pixbuf,
int src_x,
int src_y,
int width,
int height)
{
guchar *pixels;
GdkPixbuf *sub;
g_return_val_if_fail (GDK_IS_PIXBUF (src_pixbuf), NULL);
g_return_val_if_fail (src_x >= 0 && src_x + width <= src_pixbuf->width, NULL);
g_return_val_if_fail (src_y >= 0 && src_y + height <= src_pixbuf->height, NULL);
pixels = (gdk_pixbuf_get_pixels (src_pixbuf)
+ src_y * src_pixbuf->rowstride
+ src_x * src_pixbuf->n_channels);
sub = gdk_pixbuf_new_from_data (pixels,
src_pixbuf->colorspace,
src_pixbuf->has_alpha,
src_pixbuf->bits_per_sample,
width, height,
src_pixbuf->rowstride,
NULL, NULL);
/* Keep a reference to src_pixbuf */
g_object_ref (src_pixbuf);
g_object_set_qdata_full (G_OBJECT (sub),
g_quark_from_static_string ("gdk-pixbuf-subpixbuf-src"),
src_pixbuf,
(GDestroyNotify) g_object_unref);
return sub;
}
/* Accessors */
/**
* gdk_pixbuf_get_colorspace:
* @pixbuf: A pixbuf.
*
* Queries the color space of a pixbuf.
*
* Return value: Color space.
**/
GdkColorspace
gdk_pixbuf_get_colorspace (const GdkPixbuf *pixbuf)
{
g_return_val_if_fail (pixbuf != NULL, GDK_COLORSPACE_RGB);
return pixbuf->colorspace;
}
/**
* gdk_pixbuf_get_n_channels:
* @pixbuf: A pixbuf.
*
* Queries the number of channels of a pixbuf.
*
* Return value: Number of channels.
**/
int
gdk_pixbuf_get_n_channels (const GdkPixbuf *pixbuf)
{
g_return_val_if_fail (pixbuf != NULL, -1);
return pixbuf->n_channels;
}
/**
* gdk_pixbuf_get_has_alpha:
* @pixbuf: A pixbuf.
*
* Queries whether a pixbuf has an alpha channel (opacity information).
*
* Return value: %TRUE if it has an alpha channel, %FALSE otherwise.
**/
gboolean
gdk_pixbuf_get_has_alpha (const GdkPixbuf *pixbuf)
{
g_return_val_if_fail (pixbuf != NULL, FALSE);
return pixbuf->has_alpha ? TRUE : FALSE;
}
/**
* gdk_pixbuf_get_bits_per_sample:
* @pixbuf: A pixbuf.
*
* Queries the number of bits per color sample in a pixbuf.
*
* Return value: Number of bits per color sample.
**/
int
gdk_pixbuf_get_bits_per_sample (const GdkPixbuf *pixbuf)
{
g_return_val_if_fail (pixbuf != NULL, -1);
return pixbuf->bits_per_sample;
}
/**
* gdk_pixbuf_get_pixels:
* @pixbuf: A pixbuf.
*
* Queries a pointer to the pixel data of a pixbuf.
*
* Return value: A pointer to the pixbuf's pixel data. Please see <xref linkend="image-data"/>
* for information about how the pixel data is stored in
* memory.
**/
guchar *
gdk_pixbuf_get_pixels (const GdkPixbuf *pixbuf)
{
g_return_val_if_fail (pixbuf != NULL, NULL);
return pixbuf->pixels;
}
/**
* gdk_pixbuf_get_width:
* @pixbuf: A pixbuf.
*
* Queries the width of a pixbuf.
*
* Return value: Width in pixels.
**/
int
gdk_pixbuf_get_width (const GdkPixbuf *pixbuf)
{
g_return_val_if_fail (pixbuf != NULL, -1);
return pixbuf->width;
}
/**
* gdk_pixbuf_get_height:
* @pixbuf: A pixbuf.
*
* Queries the height of a pixbuf.
*
* Return value: Height in pixels.
**/
int
gdk_pixbuf_get_height (const GdkPixbuf *pixbuf)
{
g_return_val_if_fail (pixbuf != NULL, -1);
return pixbuf->height;
}
/**
* gdk_pixbuf_get_rowstride:
* @pixbuf: A pixbuf.
*
* Queries the rowstride of a pixbuf, which is the number of bytes between the start of a row
* and the start of the next row.
*
* Return value: Distance between row starts.
**/
int
gdk_pixbuf_get_rowstride (const GdkPixbuf *pixbuf)
{
g_return_val_if_fail (pixbuf != NULL, -1);
return pixbuf->rowstride;
}
/* General initialization hooks */
GDK_PIXBUF_VAR const guint gdk_pixbuf_major_version = GDK_PIXBUF_MAJOR;
GDK_PIXBUF_VAR const guint gdk_pixbuf_minor_version = GDK_PIXBUF_MINOR;
GDK_PIXBUF_VAR const guint gdk_pixbuf_micro_version = GDK_PIXBUF_MICRO;
GDK_PIXBUF_VAR const char *gdk_pixbuf_version = GDK_PIXBUF_VERSION;
/* Error quark */
GQuark
gdk_pixbuf_error_quark (void)
{
return g_quark_from_static_string ("gdk-pixbuf-error-quark");
}
/**
* gdk_pixbuf_fill:
* @pixbuf: a #GdkPixbuf
* @pixel: RGBA pixel to clear to
* (0xffffffff is opaque white, 0x00000000 transparent black)
*
* Clears a pixbuf to the given RGBA value, converting the RGBA value into
* the pixbuf's pixel format. The alpha will be ignored if the pixbuf
* doesn't have an alpha channel.
*
**/
void
gdk_pixbuf_fill (GdkPixbuf *pixbuf,
guint32 pixel)
{
guchar *pixels;
guint r, g, b, a;
guchar *p;
guint w, h;
g_return_if_fail (GDK_IS_PIXBUF (pixbuf));
if (pixbuf->width == 0 || pixbuf->height == 0)
return;
pixels = pixbuf->pixels;
r = (pixel & 0xff000000) >> 24;
g = (pixel & 0x00ff0000) >> 16;
b = (pixel & 0x0000ff00) >> 8;
a = (pixel & 0x000000ff);
h = pixbuf->height;
while (h--) {
w = pixbuf->width;
p = pixels;
switch (pixbuf->n_channels) {
case 3:
while (w--) {
p[0] = r;
p[1] = g;
p[2] = b;
p += 3;
}
break;
case 4:
while (w--) {
p[0] = r;
p[1] = g;
p[2] = b;
p[3] = a;
p += 4;
}
break;
default:
break;
}
pixels += pixbuf->rowstride;
}
}
/**
* gdk_pixbuf_get_option:
* @pixbuf: a #GdkPixbuf
* @key: a nul-terminated string.
*
* Looks up @key in the list of options that may have been attached to the
* @pixbuf when it was loaded, or that may have been attached by another
* function using gdk_pixbuf_set_option().
*
* For instance, the ANI loader provides "Title" and "Artist" options.
* The ICO, XBM, and XPM loaders provide "x_hot" and "y_hot" hot-spot
* options for cursor definitions. The PNG loader provides the tEXt ancillary
* chunk key/value pairs as options. Since 2.12, the TIFF and JPEG loaders
* return an "orientation" option string that corresponds to the embedded
* TIFF/Exif orientation tag (if present).
*
* Return value: the value associated with @key. This is a nul-terminated
* string that should not be freed or %NULL if @key was not found.
**/
G_CONST_RETURN gchar *
gdk_pixbuf_get_option (GdkPixbuf *pixbuf,
const gchar *key)
{
gchar **options;
gint i;
g_return_val_if_fail (GDK_IS_PIXBUF (pixbuf), NULL);
g_return_val_if_fail (key != NULL, NULL);
options = g_object_get_qdata (G_OBJECT (pixbuf),
g_quark_from_static_string ("gdk_pixbuf_options"));
if (options) {
for (i = 0; options[2*i]; i++) {
if (strcmp (options[2*i], key) == 0)
return options[2*i+1];
}
}
return NULL;
}
/**
* gdk_pixbuf_set_option:
* @pixbuf: a #GdkPixbuf
* @key: a nul-terminated string.
* @value: a nul-terminated string.
*
* Attaches a key/value pair as an option to a #GdkPixbuf. If %key already
* exists in the list of options attached to @pixbuf, the new value is
* ignored and %FALSE is returned.
*
* Return value: %TRUE on success.
*
* Since: 2.2
**/
gboolean
gdk_pixbuf_set_option (GdkPixbuf *pixbuf,
const gchar *key,
const gchar *value)
{
GQuark quark;
gchar **options;
gint n = 0;
g_return_val_if_fail (GDK_IS_PIXBUF (pixbuf), FALSE);
g_return_val_if_fail (key != NULL, FALSE);
g_return_val_if_fail (value != NULL, FALSE);
quark = g_quark_from_static_string ("gdk_pixbuf_options");
options = g_object_get_qdata (G_OBJECT (pixbuf), quark);
if (options) {
for (n = 0; options[2*n]; n++) {
if (strcmp (options[2*n], key) == 0)
return FALSE;
}
g_object_steal_qdata (G_OBJECT (pixbuf), quark);
options = g_renew (gchar *, options, 2*(n+1) + 1);
} else {
options = g_new (gchar *, 3);
}
options[2*n] = g_strdup (key);
options[2*n+1] = g_strdup (value);
options[2*n+2] = NULL;
g_object_set_qdata_full (G_OBJECT (pixbuf), quark,
options, (GDestroyNotify) g_strfreev);
return TRUE;
}
static void
gdk_pixbuf_set_property (GObject *object,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
GdkPixbuf *pixbuf = GDK_PIXBUF (object);
switch (prop_id)
{
case PROP_COLORSPACE:
pixbuf->colorspace = g_value_get_enum (value);
break;
case PROP_N_CHANNELS:
pixbuf->n_channels = g_value_get_int (value);
break;
case PROP_HAS_ALPHA:
pixbuf->has_alpha = g_value_get_boolean (value);
break;
case PROP_BITS_PER_SAMPLE:
pixbuf->bits_per_sample = g_value_get_int (value);
break;
case PROP_WIDTH:
pixbuf->width = g_value_get_int (value);
break;
case PROP_HEIGHT:
pixbuf->height = g_value_get_int (value);
break;
case PROP_ROWSTRIDE:
pixbuf->rowstride = g_value_get_int (value);
break;
case PROP_PIXELS:
pixbuf->pixels = (guchar *) g_value_get_pointer (value);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gdk_pixbuf_get_property (GObject *object,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
GdkPixbuf *pixbuf = GDK_PIXBUF (object);
switch (prop_id)
{
case PROP_COLORSPACE:
g_value_set_enum (value, gdk_pixbuf_get_colorspace (pixbuf));
break;
case PROP_N_CHANNELS:
g_value_set_int (value, gdk_pixbuf_get_n_channels (pixbuf));
break;
case PROP_HAS_ALPHA:
g_value_set_boolean (value, gdk_pixbuf_get_has_alpha (pixbuf));
break;
case PROP_BITS_PER_SAMPLE:
g_value_set_int (value, gdk_pixbuf_get_bits_per_sample (pixbuf));
break;
case PROP_WIDTH:
g_value_set_int (value, gdk_pixbuf_get_width (pixbuf));
break;
case PROP_HEIGHT:
g_value_set_int (value, gdk_pixbuf_get_height (pixbuf));
break;
case PROP_ROWSTRIDE:
g_value_set_int (value, gdk_pixbuf_get_rowstride (pixbuf));
break;
case PROP_PIXELS:
g_value_set_pointer (value, gdk_pixbuf_get_pixels (pixbuf));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
#define __GDK_PIXBUF_C__
#include "gdk-pixbuf-aliasdef.c"