cairo-xlib-surface.c

按照官方的说法：Cairo is a vector graphics library with cross-device output support. 翻译过来

/* cairo - a vector graphics library with display and print output
 *
 * Copyright © 2002 University of Southern California
 * Copyright © 2005 Red Hat, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it either under the terms of the GNU Lesser General Public
 * License version 2.1 as published by the Free Software Foundation
 * (the "LGPL") or, at your option, under the terms of the Mozilla
 * Public License Version 1.1 (the "MPL"). If you do not alter this
 * notice, a recipient may use your version of this file under either
 * the MPL or the LGPL.
 *
 * You should have received a copy of the LGPL along with this library
 * in the file COPYING-LGPL-2.1; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 * You should have received a copy of the MPL along with this library
 * in the file COPYING-MPL-1.1
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
 * OF ANY KIND, either express or implied. See the LGPL or the MPL for
 * the specific language governing rights and limitations.
 *
 * The Original Code is the cairo graphics library.
 *
 * The Initial Developer of the Original Code is University of Southern
 * California.
 *
 * Contributor(s):
 *	Carl D. Worth <[e-mail]>
 */

#include "cairoint.h"
#include "cairo-xlib.h"
#include "cairo-xlib-xrender.h"
#include "cairo-xlib-test.h"
#include "cairo-xlib-private.h"
#include "cairo-clip-private.h"
#include <X11/extensions/Xrender.h>
#include <X11/extensions/renderproto.h>

/* Xlib doesn't define a typedef, so define one ourselves */
typedef int (*cairo_xlib_error_func_t) (Display     *display,
					XErrorEvent *event);

typedef struct _cairo_xlib_surface cairo_xlib_surface_t;

static void
_cairo_xlib_surface_ensure_gc (cairo_xlib_surface_t *surface);

static void
_cairo_xlib_surface_ensure_src_picture (cairo_xlib_surface_t *surface);

static void
_cairo_xlib_surface_ensure_dst_picture (cairo_xlib_surface_t *surface);

static cairo_bool_t
_cairo_surface_is_xlib (cairo_surface_t *surface);

static cairo_bool_t
_native_byte_order_lsb (void);

static cairo_int_status_t
_cairo_xlib_surface_show_glyphs (void                *abstract_dst,
				 cairo_operator_t     op,
				 cairo_pattern_t     *src_pattern,
				 const cairo_glyph_t *glyphs,
				 int		      num_glyphs,
				 cairo_scaled_font_t *scaled_font);

/*
 * Instead of taking two round trips for each blending request,
 * assume that if a particular drawable fails GetImage that it will
 * fail for a "while"; use temporary pixmaps to avoid the errors
 */

#define CAIRO_ASSUME_PIXMAP	20

struct _cairo_xlib_surface {
    cairo_surface_t base;

    Display *dpy;
    cairo_xlib_screen_info_t *screen_info;

    GC gc;
    Drawable drawable;
    Screen *screen;
    cairo_bool_t owns_pixmap;
    Visual *visual;

    int use_pixmap;

    int render_major;
    int render_minor;

    /* TRUE if the server has a bug with repeating pictures
     *
     *  https://bugs.freedesktop.org/show_bug.cgi?id=3566
     *
     * We can't test for this because it depends on whether the
     * picture is in video memory or not.
     *
     * We also use this variable as a guard against a second
     * independent bug with transformed repeating pictures:
     *
     * http://lists.freedesktop.org/archives/cairo/2004-September/001839.html
     *
     * Both are fixed in xorg >= 6.9 and hopefully in > 6.8.2, so
     * we can reuse the test for now.
     */
    cairo_bool_t buggy_repeat;

    int width;
    int height;
    int depth;

    Picture dst_picture, src_picture;

    cairo_bool_t have_clip_rects;
    XRectangle *clip_rects;
    int num_clip_rects;

    XRenderPictFormat *xrender_format;
};

#define CAIRO_SURFACE_RENDER_AT_LEAST(surface, major, minor)	\
	(((surface)->render_major > major) ||			\
	 (((surface)->render_major == major) && ((surface)->render_minor >= minor)))

#define CAIRO_SURFACE_RENDER_HAS_CREATE_PICTURE(surface)		CAIRO_SURFACE_RENDER_AT_LEAST((surface), 0, 0)
#define CAIRO_SURFACE_RENDER_HAS_COMPOSITE(surface)		CAIRO_SURFACE_RENDER_AT_LEAST((surface), 0, 0)
#define CAIRO_SURFACE_RENDER_HAS_COMPOSITE_TEXT(surface)	CAIRO_SURFACE_RENDER_AT_LEAST((surface), 0, 0)

#define CAIRO_SURFACE_RENDER_HAS_FILL_RECTANGLE(surface)		CAIRO_SURFACE_RENDER_AT_LEAST((surface), 0, 1)
#define CAIRO_SURFACE_RENDER_HAS_FILL_RECTANGLES(surface)		CAIRO_SURFACE_RENDER_AT_LEAST((surface), 0, 1)

#define CAIRO_SURFACE_RENDER_HAS_DISJOINT(surface)			CAIRO_SURFACE_RENDER_AT_LEAST((surface), 0, 2)
#define CAIRO_SURFACE_RENDER_HAS_CONJOINT(surface)			CAIRO_SURFACE_RENDER_AT_LEAST((surface), 0, 2)

#define CAIRO_SURFACE_RENDER_HAS_TRAPEZOIDS(surface)		CAIRO_SURFACE_RENDER_AT_LEAST((surface), 0, 4)
#define CAIRO_SURFACE_RENDER_HAS_TRIANGLES(surface)		CAIRO_SURFACE_RENDER_AT_LEAST((surface), 0, 4)
#define CAIRO_SURFACE_RENDER_HAS_TRISTRIP(surface)			CAIRO_SURFACE_RENDER_AT_LEAST((surface), 0, 4)
#define CAIRO_SURFACE_RENDER_HAS_TRIFAN(surface)			CAIRO_SURFACE_RENDER_AT_LEAST((surface), 0, 4)

#define CAIRO_SURFACE_RENDER_HAS_PICTURE_TRANSFORM(surface)	CAIRO_SURFACE_RENDER_AT_LEAST((surface), 0, 6)
#define CAIRO_SURFACE_RENDER_HAS_FILTERS(surface)	CAIRO_SURFACE_RENDER_AT_LEAST((surface), 0, 6)

static cairo_bool_t cairo_xlib_render_disabled = FALSE;

/**
 * _cairo_xlib_test_disable_render:
 *
 * Disables the use of the RENDER extension.
 *
 * <note>
 * This function is <emphasis>only</emphasis> intended for internal
 * testing use within the cairo distribution. It is not installed in
 * any public header file.
 * </note>
 **/
void
_cairo_xlib_test_disable_render (void)
{
    cairo_xlib_render_disabled = TRUE;
}

static int
_CAIRO_FORMAT_DEPTH (cairo_format_t format)
{
    switch (format) {
    case CAIRO_FORMAT_A1:
	return 1;
    case CAIRO_FORMAT_A8:
	return 8;
    case CAIRO_FORMAT_RGB24:
	return 24;
    case CAIRO_FORMAT_ARGB32:
    default:
	return 32;
    }
}

static XRenderPictFormat *
_CAIRO_FORMAT_TO_XRENDER_FORMAT(Display *dpy, cairo_format_t format)
{
    int	pict_format;
    switch (format) {
    case CAIRO_FORMAT_A1:
	pict_format = PictStandardA1; break;
    case CAIRO_FORMAT_A8:
	pict_format = PictStandardA8; break;
    case CAIRO_FORMAT_RGB24:
	pict_format = PictStandardRGB24; break;
    case CAIRO_FORMAT_ARGB32:
    default:
	pict_format = PictStandardARGB32; break;
    }
    return XRenderFindStandardFormat (dpy, pict_format);
}

static cairo_surface_t *
_cairo_xlib_surface_create_similar_with_format (void	       *abstract_src,
						cairo_format_t	format,
						int		width,
						int		height)
{
    cairo_xlib_surface_t *src = abstract_src;
    Display *dpy = src->dpy;
    Pixmap pix;
    cairo_xlib_surface_t *surface;
    int depth = _CAIRO_FORMAT_DEPTH (format);
    XRenderPictFormat *xrender_format = _CAIRO_FORMAT_TO_XRENDER_FORMAT (dpy,
									 format);

    /* As a good first approximation, if the display doesn't have even
     * the most elementary RENDER operation, then we're better off
     * using image surfaces for all temporary operations
     */
    if (!CAIRO_SURFACE_RENDER_HAS_COMPOSITE(src)) {
	return cairo_image_surface_create (format, width, height);
    }

    pix = XCreatePixmap (dpy, RootWindowOfScreen (src->screen),
			 width <= 0 ? 1 : width, height <= 0 ? 1 : height,
			 depth);

    surface = (cairo_xlib_surface_t *)
	cairo_xlib_surface_create_with_xrender_format (dpy, pix, src->screen,
						       xrender_format,
						       width, height);
    if (surface->base.status != CAIRO_STATUS_SUCCESS) {
	_cairo_error (CAIRO_STATUS_NO_MEMORY);
	return (cairo_surface_t*) &_cairo_surface_nil;
    }

    surface->owns_pixmap = TRUE;

    return &surface->base;
}

static cairo_content_t
_xrender_format_to_content (XRenderPictFormat *xrender_format)
{
    cairo_bool_t xrender_format_has_alpha;
    cairo_bool_t xrender_format_has_color;

    /* This only happens when using a non-Render server. Let's punt
     * and say there's no alpha here. */
    if (xrender_format == NULL)
	return CAIRO_CONTENT_COLOR;

    xrender_format_has_alpha = (xrender_format->direct.alpha != 0);
    xrender_format_has_color = (xrender_format->direct.red   != 0 ||
				xrender_format->direct.green != 0 ||
				xrender_format->direct.blue  != 0);

    if (xrender_format_has_alpha)
	if (xrender_format_has_color)
	    return CAIRO_CONTENT_COLOR_ALPHA;
	else
	    return CAIRO_CONTENT_ALPHA;
    else
	return CAIRO_CONTENT_COLOR;
}

static cairo_surface_t *
_cairo_xlib_surface_create_similar (void	       *abstract_src,
				    cairo_content_t	content,
				    int			width,
				    int			height)
{
    cairo_xlib_surface_t *src = abstract_src;
    XRenderPictFormat *xrender_format = src->xrender_format;
    cairo_xlib_surface_t *surface;
    Pixmap pix;

    /* Start by examining the surface's XRenderFormat, or if it
     * doesn't have one, then look one up through its visual (in the
     * case of a bitmap, it won't even have that). */
    if (xrender_format == NULL && src->visual != NULL)
        xrender_format = XRenderFindVisualFormat (src->dpy, src->visual);

    /* If we never found an XRenderFormat or if it isn't compatible
     * with the content being requested, then we fallback to just
     * constructing a cairo_format_t instead, (which will fairly
     * arbitrarily pick a visual/depth for the similar surface.
     */
    if (xrender_format == NULL ||
	_xrender_format_to_content (xrender_format) != content)
    {
	return _cairo_xlib_surface_create_similar_with_format (abstract_src,
							       _cairo_format_from_content (content),
							       width, height);
    }

    /* We've got a compatible XRenderFormat now, which means the
     * similar surface will match the existing surface as closely in
     * visual/depth etc. as possible. */
    pix = XCreatePixmap (src->dpy, RootWindowOfScreen (src->screen),
			 width <= 0 ? 1 : width, height <= 0 ? 1 : height,
			 xrender_format->depth);

    surface = (cairo_xlib_surface_t *)
	cairo_xlib_surface_create_with_xrender_format (src->dpy, pix,
						       src->screen,
						       xrender_format,
						       width, height);
    if (surface->base.status != CAIRO_STATUS_SUCCESS) {
	_cairo_error (CAIRO_STATUS_NO_MEMORY);
	return (cairo_surface_t*) &_cairo_surface_nil;
    }

    surface->owns_pixmap = TRUE;

    return &surface->base;
}

static cairo_status_t
_cairo_xlib_surface_finish (void *abstract_surface)
{
    cairo_xlib_surface_t *surface = abstract_surface;
    if (surface->dst_picture != None)
	XRenderFreePicture (surface->dpy, surface->dst_picture);

    if (surface->src_picture != None)
	XRenderFreePicture (surface->dpy, surface->src_picture);

    if (surface->owns_pixmap)
	XFreePixmap (surface->dpy, surface->drawable);

    if (surface->gc != NULL)
	XFreeGC (surface->dpy, surface->gc);

    if (surface->clip_rects != NULL)
	free (surface->clip_rects);

    surface->dpy = NULL;

    return CAIRO_STATUS_SUCCESS;
}

static int
_noop_error_handler (Display     *display,
		     XErrorEvent *event)
{
    return False;		/* return value is ignored */
}

static cairo_bool_t
_CAIRO_MASK_FORMAT (cairo_format_masks_t *masks, cairo_format_t *format)
{
    switch (masks->bpp) {
    case 32:
	if (masks->alpha_mask == 0xff000000 &&
	    masks->red_mask == 0x00ff0000 &&
	    masks->green_mask == 0x0000ff00 &&
	    masks->blue_mask == 0x000000ff)
	{
	    *format = CAIRO_FORMAT_ARGB32;
	    return True;
	}
	if (masks->alpha_mask == 0x00000000 &&
	    masks->red_mask == 0x00ff0000 &&
	    masks->green_mask == 0x0000ff00 &&
	    masks->blue_mask == 0x000000ff)
	{
	    *format = CAIRO_FORMAT_RGB24;
	    return True;
	}
	break;
    case 8:
	if (masks->alpha_mask == 0xff)
	{
	    *format = CAIRO_FORMAT_A8;
	    return True;
	}
	break;
    case 1:
	if (masks->alpha_mask == 0x1)
	{
	    *format = CAIRO_FORMAT_A1;
	    return True;
	}
	break;
    }
    return False;
}

static void
_swap_ximage_2bytes (XImage *ximage)
{
    int i, j;
    char *line = ximage->data;

    for (j = ximage->height; j; j--) {
	uint16_t *p = (uint16_t *)line;
	for (i = ximage->width; i; i--) {
	    *p = (((*p & 0x00ff) << 8) |
		  ((*p)          >> 8));
	    p++;
	}

	line += ximage->bytes_per_line;
    }
}

static void
_swap_ximage_4bytes (XImage *ximage)
{
    int i, j;
    char *line = ximage->data;

    for (j = ximage->height; j; j--) {
	uint32_t *p = (uint32_t *)line;
	for (i = ximage->width; i; i--) {
	    *p = (((*p & 0x000000ff) << 24) |
		  ((*p & 0x0000ff00) << 8) |
		  ((*p & 0x00ff0000) >> 8) |
		  ((*p)              >> 24));
	    p++;
	}

	line += ximage->bytes_per_line;
    }
}

static void
_swap_ximage_bits (XImage *ximage)
{
    int i, j;
    char *line = ximage->data;
    int unit = ximage->bitmap_unit;
    int line_bytes = ((ximage->width + unit - 1) & ~(unit - 1)) / 8;

    for (j = ximage->height; j; j--) {
	char *p = line;

	for (i = line_bytes; i; i--) {
	    char b = *p;
	    b = ((b << 1) & 0xaa) | ((b >> 1) & 0x55);
	    b = ((b << 2) & 0xcc) | ((b >> 2) & 0x33);
	    b = ((b << 4) & 0xf0) | ((b >> 4) & 0x0f);
	    *p = b;

	    p++;
	}

	line += ximage->bytes_per_line;
    }
}

static void
_swap_ximage_to_native (XImage *ximage)
{
    int unit_bytes = 0;
    int native_byte_order = _native_byte_order_lsb () ? LSBFirst : MSBFirst;

    if (ximage->bits_per_pixel == 1 &&