cairo-xcb-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
 *
 * 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-xcb.h"
#include "cairo-xcb-xrender.h"

#define AllPlanes               ((unsigned long)~0L)

static XCBRenderPICTFORMAT
format_from_visual(XCBConnection *c, XCBVISUALID visual)
{
    static const XCBRenderPICTFORMAT nil = { 0 };
    XCBRenderQueryPictFormatsRep *r;
    XCBRenderPICTSCREENIter si;
    XCBRenderPICTDEPTHIter di;
    XCBRenderPICTVISUALIter vi;

    r = XCBRenderQueryPictFormatsReply(c, XCBRenderQueryPictFormats(c), 0);
    if(!r)
	return nil;

    for(si = XCBRenderQueryPictFormatsScreensIter(r); si.rem; XCBRenderPICTSCREENNext(&si))
	for(di = XCBRenderPICTSCREENDepthsIter(si.data); di.rem; XCBRenderPICTDEPTHNext(&di))
	    for(vi = XCBRenderPICTDEPTHVisualsIter(di.data); vi.rem; XCBRenderPICTVISUALNext(&vi))
		if(vi.data->visual.id == visual.id)
		{
		    XCBRenderPICTFORMAT ret = vi.data->format;
		    free(r);
		    return ret;
		}

    return nil;
}

static cairo_content_t
_xcb_render_format_to_content (XCBRenderPICTFORMINFO *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_mask != 0);
    xrender_format_has_color = (xrender_format->direct.red_mask   != 0 ||
				xrender_format->direct.green_mask != 0 ||
				xrender_format->direct.blue_mask  != 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;

}

/* XXX: Why is this ridiculously complex compared to the equivalent
 * function in cairo-xlib-surface.c */
static XCBRenderPICTFORMINFO
_format_from_cairo(XCBConnection *c, cairo_format_t fmt)
{
    XCBRenderPICTFORMINFO ret = {{ 0 }};
    struct tmpl_t {
	XCBRenderDIRECTFORMAT direct;
	CARD8 depth;
    };
    static const struct tmpl_t templates[] = {
	/* CAIRO_FORMAT_ARGB32 */
	{
	    {
		16, 0xff,
		8,  0xff,
		0,  0xff,
		24, 0xff
	    },
	    32
	},
	/* CAIRO_FORMAT_RGB24 */
	{
	    {
		16, 0xff,
		8,  0xff,
		0,  0xff,
		0,  0x00
	    },
	    24
	},
	/* CAIRO_FORMAT_A8 */
	{
	    {
		0,  0x00,
		0,  0x00,
		0,  0x00,
		0,  0xff
	    },
	    8
	},
	/* CAIRO_FORMAT_A1 */
	{
	    {
		0,  0x00,
		0,  0x00,
		0,  0x00,
		0,  0x01
	    },
	    1
	},
    };
    const struct tmpl_t *tmpl;
    XCBRenderQueryPictFormatsRep *r;
    XCBRenderPICTFORMINFOIter fi;

    if(fmt < 0 || fmt >= (sizeof(templates) / sizeof(*templates)))
	return ret;
    tmpl = templates + fmt;

    r = XCBRenderQueryPictFormatsReply(c, XCBRenderQueryPictFormats(c), 0);
    if(!r)
	return ret;

    for(fi = XCBRenderQueryPictFormatsFormatsIter(r); fi.rem; XCBRenderPICTFORMINFONext(&fi))
    {
	const XCBRenderDIRECTFORMAT *t, *f;
	if(fi.data->type != XCBRenderPictTypeDirect)
	    continue;
	if(fi.data->depth != tmpl->depth)
	    continue;
	t = &tmpl->direct;
	f = &fi.data->direct;
	if(t->red_mask && (t->red_mask != f->red_mask || t->red_shift != f->red_shift))
	    continue;
	if(t->green_mask && (t->green_mask != f->green_mask || t->green_shift != f->green_shift))
	    continue;
	if(t->blue_mask && (t->blue_mask != f->blue_mask || t->blue_shift != f->blue_shift))
	    continue;
	if(t->alpha_mask && (t->alpha_mask != f->alpha_mask || t->alpha_shift != f->alpha_shift))
	    continue;

	ret = *fi.data;
    }

    free(r);
    return ret;
}

/*
 * 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

typedef struct cairo_xcb_surface {
    cairo_surface_t base;

    XCBConnection *dpy;
    XCBSCREEN *screen;

    XCBGCONTEXT gc;
    XCBDRAWABLE drawable;
    int owns_pixmap;
    XCBVISUALTYPE *visual;

    int use_pixmap;

    int render_major;
    int render_minor;

    int width;
    int height;
    int depth;

    XCBRenderPICTURE picture;
    XCBRenderPICTFORMINFO format;
    int has_format;
} cairo_xcb_surface_t;

#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_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 void
_cairo_xcb_surface_ensure_gc (cairo_xcb_surface_t *surface);

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 cairo_surface_t *
_cairo_xcb_surface_create_similar (void		       *abstract_src,
				   cairo_content_t	content,
				   int			width,
				   int			height)
{
    cairo_xcb_surface_t *src = abstract_src;
    XCBConnection *dpy = src->dpy;
    XCBDRAWABLE d;
    cairo_xcb_surface_t *surface;
    cairo_format_t format = _cairo_format_from_content (content);
    XCBRenderPICTFORMINFO xrender_format = _format_from_cairo (dpy, format);

    /* As a good first approximation, if the display doesn't have COMPOSITE,
     * 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);
    }

    d.pixmap = XCBPIXMAPNew (dpy);
    XCBCreatePixmap (dpy, _CAIRO_FORMAT_DEPTH (format),
		     d.pixmap, src->drawable,
		     width <= 0 ? 1 : width,
		     height <= 0 ? 1 : height);

    surface = (cairo_xcb_surface_t *)
	cairo_xcb_surface_create_with_xrender_format (dpy, d, src->screen,
						      &xrender_format,
						      width, height);
    if (surface->base.status) {
	_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_xcb_surface_finish (void *abstract_surface)
{
    cairo_xcb_surface_t *surface = abstract_surface;
    if (surface->picture.xid)
	XCBRenderFreePicture (surface->dpy, surface->picture);

    if (surface->owns_pixmap)
	XCBFreePixmap (surface->dpy, surface->drawable.pixmap);

    if (surface->gc.xid)
	XCBFreeGC (surface->dpy, surface->gc);

    surface->dpy = NULL;

    return CAIRO_STATUS_SUCCESS;
}

static int
_bits_per_pixel(XCBConnection *c, int depth)
{
    XCBFORMAT *fmt = XCBSetupPixmapFormats(XCBGetSetup(c));
    XCBFORMAT *fmtend = fmt + XCBSetupPixmapFormatsLength(XCBGetSetup(c));

    for(; fmt != fmtend; ++fmt)
	if(fmt->depth == depth)
	    return fmt->bits_per_pixel;

    if(depth <= 4)
	return 4;
    if(depth <= 8)
	return 8;
    if(depth <= 16)
	return 16;
    return 32;
}

static int
_bytes_per_line(XCBConnection *c, int width, int bpp)
{
    int bitmap_pad = XCBGetSetup(c)->bitmap_format_scanline_pad;
    return ((bpp * width + bitmap_pad - 1) & -bitmap_pad) >> 3;
}

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 cairo_status_t
_get_image_surface (cairo_xcb_surface_t     *surface,
		    cairo_rectangle_int16_t *interest_rect,
		    cairo_image_surface_t  **image_out,
		    cairo_rectangle_int16_t *image_rect)
{
    cairo_image_surface_t *image;
    XCBGetImageRep *imagerep;
    int bpp, bytes_per_line;
    int x1, y1, x2, y2;
    unsigned char *data;
    cairo_format_t format;
    cairo_format_masks_t masks;

    x1 = 0;
    y1 = 0;
    x2 = surface->width;
    y2 = surface->height;

    if (interest_rect) {
	cairo_rectangle_int16_t rect;

	rect.x = interest_rect->x;
	rect.y = interest_rect->y;
	rect.width = interest_rect->width;
	rect.height = interest_rect->height;

	if (rect.x > x1)
	    x1 = rect.x;
	if (rect.y > y1)
	    y1 = rect.y;
	if (rect.x + rect.width < x2)
	    x2 = rect.x + rect.width;
	if (rect.y + rect.height < y2)
	    y2 = rect.y + rect.height;

	if (x1 >= x2 || y1 >= y2) {
	    *image_out = NULL;
	    return CAIRO_STATUS_SUCCESS;
	}
    }

    if (image_rect) {
	image_rect->x = x1;
	image_rect->y = y1;
	image_rect->width = x2 - x1;
	image_rect->height = y2 - y1;
    }

    /* XXX: This should try to use the XShm extension if available */

    if (surface->use_pixmap == 0)
    {
	XCBGenericError *error;
	imagerep = XCBGetImageReply(surface->dpy,
				    XCBGetImage(surface->dpy, XCBImageFormatZPixmap,
						surface->drawable,
						x1, y1,
						x2 - x1, y2 - y1,
						AllPlanes), &error);

	/* If we get an error, the surface must have been a window,
	 * so retry with the safe code path.
	 */
	if (error)
	    surface->use_pixmap = CAIRO_ASSUME_PIXMAP;
    }
    else
    {
	surface->use_pixmap--;
	imagerep = NULL;
    }

    if (!imagerep)
    {
	/* XCBGetImage from a window is dangerous because it can
	 * produce errors if the window is unmapped or partially
	 * outside the screen. We could check for errors and