cairo-beos-surface.cpp

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

    cairo_beos_surface_t *surface = reinterpret_cast<cairo_beos_surface_t*>(
							abstract_surface);
    AutoLockView locker(surface->view);
    if (!locker)
	return CAIRO_STATUS_NO_MEMORY; /// XXX not exactly right, but what can we do?


    surface->view->Sync();

    if (surface->bitmap) {
	*image_out = _cairo_beos_bitmap_to_surface(surface->bitmap);
	if (!*image_out)
	    return CAIRO_STATUS_NO_MEMORY;

	*image_extra = NULL;
	return CAIRO_STATUS_SUCCESS;
    }

    BBitmap* bmp;
    if (_cairo_beos_view_to_bitmap(surface->view, &bmp) != OK)
	return CAIRO_STATUS_NO_MEMORY; /// XXX incorrect if the error was NOT_VISIBLE

    *image_out = _cairo_beos_bitmap_to_surface(bmp);
    if (!*image_out) {
	delete bmp;
	return CAIRO_STATUS_NO_MEMORY;
    }
    *image_extra = bmp;

    return CAIRO_STATUS_SUCCESS;
}

static void
_cairo_beos_surface_release_source_image (void                  *abstract_surface,
					  cairo_image_surface_t *image,
					  void                  *image_extra)
{
    cairo_surface_destroy (&image->base);

    BBitmap* bmp = static_cast<BBitmap*>(image_extra);
    delete bmp;
}



static cairo_status_t
_cairo_beos_surface_acquire_dest_image (void			 *abstract_surface,
                                        cairo_rectangle_fixed_t	 *interest_rect,
                                        cairo_image_surface_t	**image_out,
                                        cairo_rectangle_fixed_t	 *image_rect,
                                        void			**image_extra)
{
    cairo_beos_surface_t *surface = reinterpret_cast<cairo_beos_surface_t*>(
							abstract_surface);

    AutoLockView locker(surface->view);
    if (!locker) {
	*image_out = NULL;
	*image_extra = NULL;
	return CAIRO_STATUS_SUCCESS;
    }

    if (surface->bitmap) {
	surface->view->Sync();
	*image_out = _cairo_beos_bitmap_to_surface(surface->bitmap);
	if (!*image_out)
	    return CAIRO_STATUS_NO_MEMORY;

	image_rect->x = 0;
	image_rect->y = 0;
	image_rect->width = (*image_out)->width;
	image_rect->height = (*image_out)->height;

	*image_extra = NULL;
	return CAIRO_STATUS_SUCCESS;
    }

    BRect b_interest_rect(_cairo_rect_to_brect(interest_rect));

    BRect rect;
    BBitmap* bitmap;
    ViewCopyStatus status = _cairo_beos_view_to_bitmap(surface->view, &bitmap,
	                                               &rect, &b_interest_rect);
    if (status == NOT_VISIBLE) {
	*image_out = NULL;
	*image_extra = NULL;
	return CAIRO_STATUS_SUCCESS;
    }
    if (status == ERROR)
	return CAIRO_STATUS_NO_MEMORY;

    *image_rect = _brect_to_cairo_rect(rect);

#if 0
    fprintf(stderr, "Requested: (cairo rects) (%ix%i) dim (%u, %u) returning (%ix%i) dim (%u, %u)\n",
	    interest_rect->x, interest_rect->y, interest_rect->width, interest_rect->height,
	    image_rect->x, image_rect->y, image_rect->width, image_rect->height);
#endif

    *image_out = _cairo_beos_bitmap_to_surface(bitmap);
    delete bitmap;
    if (!*image_out)
	return CAIRO_STATUS_NO_MEMORY;

    *image_extra = NULL;

    return CAIRO_STATUS_SUCCESS;
}


static void
_cairo_beos_surface_release_dest_image (void			*abstract_surface,
                                        cairo_rectangle_fixed_t	*intersect_rect,
                                        cairo_image_surface_t	*image,
                                        cairo_rectangle_fixed_t	*image_rect,
                                        void			*image_extra)
{
    fprintf(stderr, "Fallback drawing\n");

    cairo_beos_surface_t *surface = reinterpret_cast<cairo_beos_surface_t*>(
							abstract_surface);

    AutoLockView locker(surface->view);
    if (!locker)
	return;

    BBitmap* bitmap_to_draw = _cairo_image_surface_to_bitmap(image);
    surface->view->PushState();

	surface->view->SetDrawingMode(B_OP_COPY);
	BRect rect(_cairo_rect_to_brect(image_rect));

	surface->view->DrawBitmap(bitmap_to_draw, rect);

    surface->view->PopState();

    delete bitmap_to_draw;
    cairo_surface_destroy(&image->base);
}

static cairo_int_status_t
_cairo_beos_surface_composite (cairo_operator_t		op,
			       cairo_pattern_t	       *src,
			       cairo_pattern_t	       *mask,
			       void		       *dst,
			       int		 	src_x,
			       int			src_y,
			       int			mask_x,
			       int			mask_y,
			       int			dst_x,
			       int			dst_y,
			       unsigned int		width,
			       unsigned int		height)
{
    cairo_beos_surface_t *surface = reinterpret_cast<cairo_beos_surface_t*>(
							dst);
    AutoLockView locker(surface->view);
    if (!locker)
	return CAIRO_INT_STATUS_SUCCESS;

    drawing_mode mode;
    if (!_cairo_op_to_be_op(op, &mode))
	return CAIRO_INT_STATUS_UNSUPPORTED;

    // XXX Masks are not yet supported
    if (mask)
	return CAIRO_INT_STATUS_UNSUPPORTED;

    // XXX should eventually support the others
    if (src->type != CAIRO_PATTERN_TYPE_SURFACE ||
	src->extend != CAIRO_EXTEND_NONE)
    {
	return CAIRO_INT_STATUS_UNSUPPORTED;
    }

    // Can we maybe support other matrices as well? (scale? if the filter is right)
    int itx, ity;
    if (!_cairo_matrix_is_integer_translation(&src->matrix, &itx, &ity))
	return CAIRO_INT_STATUS_UNSUPPORTED;

    BRect srcRect(src_x + itx,
		  src_y + ity,
		  src_x + itx + width - 1,
		  src_y + ity + height - 1);
    BRect dstRect(dst_x, dst_y, dst_x + width - 1, dst_y + height - 1);

    cairo_surface_t* src_surface = reinterpret_cast<cairo_surface_pattern_t*>(src)->
					surface;

    // Get a bitmap
    BBitmap* bmp = NULL;
    bool free_bmp = false;
    if (_cairo_surface_is_image(src_surface)) {
	cairo_image_surface_t* img_surface =
	    reinterpret_cast<cairo_image_surface_t*>(src_surface);

	bmp = _cairo_image_surface_to_bitmap(img_surface);
	free_bmp = true;
    } else if (src_surface->backend == surface->base.backend) {
	cairo_beos_surface_t *beos_surface =
	    reinterpret_cast<cairo_beos_surface_t*>(src_surface);
	if (beos_surface->bitmap) {
	    AutoLockView locker(beos_surface->view);
	    if (locker)
		beos_surface->view->Sync();
	    bmp = beos_surface->bitmap;
	} else {
	    _cairo_beos_view_to_bitmap(surface->view, &bmp);
	    free_bmp = true;
	}
    }

    if (!bmp)
	return CAIRO_INT_STATUS_UNSUPPORTED;

    // So, BeOS seems to screw up painting an opaque bitmap onto a
    // translucent one (it makes them partly transparent). Just return
    // unsupported.
    if (bmp->ColorSpace() == B_RGB32 && surface->bitmap &&
	surface->bitmap->ColorSpace() == B_RGBA32 &&
	(mode == B_OP_COPY || mode == B_OP_ALPHA))
    {
	if (free_bmp)
	    delete bmp;
	return CAIRO_INT_STATUS_UNSUPPORTED;
    }

    fprintf(stderr, "Composite\n");

    // Draw it on screen.
    surface->view->PushState();

	// If our image rect is only a subrect of the desired size, and we
	// aren't using B_OP_ALPHA, then we need to fill the rect first.
	if (mode == B_OP_COPY && !bmp->Bounds().Contains(srcRect)) {
	    rgb_color black = { 0, 0, 0, 0 };

	    surface->view->SetDrawingMode(mode);
	    surface->view->SetHighColor(black);
	    surface->view->FillRect(dstRect);
	}

	if (mode == B_OP_ALPHA && bmp->ColorSpace() == B_RGB32) {
	    mode = B_OP_COPY;
	}
	surface->view->SetDrawingMode(mode);

	if (surface->bitmap && surface->bitmap->ColorSpace() == B_RGBA32)
	    surface->view->SetBlendingMode(B_PIXEL_ALPHA, B_ALPHA_COMPOSITE);
	else
	    surface->view->SetBlendingMode(B_PIXEL_ALPHA, B_ALPHA_OVERLAY);

	surface->view->DrawBitmap(bmp, srcRect, dstRect);

    surface->view->PopState();

    if (free_bmp)
	delete bmp;

    return CAIRO_INT_STATUS_SUCCESS;
}


static void
_cairo_beos_surface_fill_rectangle (cairo_beos_surface_t	*surface,
				    cairo_rectangle_fixed_t	*rect)
{
    BRect brect(_cairo_rect_to_brect(rect));
    surface->view->FillRect(brect);
}

static cairo_int_status_t
_cairo_beos_surface_fill_rectangles (void			*abstract_surface,
				     cairo_operator_t		 op,
				     const cairo_color_t	*color,
				     cairo_rectangle_fixed_t	*rects,
				     int			 num_rects)
{
    fprintf(stderr, "Drawing %i rectangles\n", num_rects);
    cairo_beos_surface_t *surface = reinterpret_cast<cairo_beos_surface_t*>(
							abstract_surface);

    if (num_rects <= 0)
	return CAIRO_INT_STATUS_SUCCESS;

    AutoLockView locker(surface->view);
    if (!locker)
	return CAIRO_INT_STATUS_SUCCESS;

    drawing_mode mode;
    if (!_cairo_op_to_be_op(op, &mode))
	return CAIRO_INT_STATUS_UNSUPPORTED;

    rgb_color be_color = _cairo_color_to_be_color(color);

    if (mode == B_OP_ALPHA && be_color.alpha == 0xFF)
	mode = B_OP_COPY;

    // For CAIRO_OPERATOR_SOURCE, cairo expects us to use the premultiplied
    // color info. This is only relevant when drawing into an rgb24 buffer
    // (as for others, we can convert when asked for the image)
    if (mode == B_OP_COPY && be_color.alpha != 0xFF &&
	(!surface->bitmap || surface->bitmap->ColorSpace() != B_RGBA32))
    {
	be_color.red = premultiply(be_color.red, be_color.alpha);
	be_color.green = premultiply(be_color.green, be_color.alpha);
	be_color.blue = premultiply(be_color.blue, be_color.alpha);
    }

    surface->view->PushState();

	surface->view->SetDrawingMode(mode);
	surface->view->SetHighColor(be_color);
	if (surface->bitmap && surface->bitmap->ColorSpace() == B_RGBA32)
	    surface->view->SetBlendingMode(B_CONSTANT_ALPHA, B_ALPHA_COMPOSITE);
	else
	    surface->view->SetBlendingMode(B_CONSTANT_ALPHA, B_ALPHA_OVERLAY);

	for (int i = 0; i < num_rects; ++i) {
	    _cairo_beos_surface_fill_rectangle(surface, &rects[i]);
	}

    surface->view->PopState();

    return CAIRO_INT_STATUS_SUCCESS;
}



static cairo_int_status_t
_cairo_beos_surface_set_clip_region (void              *abstract_surface,
                                     pixman_region16_t *region)
{
    fprintf(stderr, "Setting clip region\n");
    cairo_beos_surface_t *surface = reinterpret_cast<cairo_beos_surface_t*>(
							abstract_surface);
    AutoLockView locker(surface->view);
    if (!locker)
	return CAIRO_INT_STATUS_SUCCESS;

    if (region == NULL) {
	// No clipping
	surface->view->ConstrainClippingRegion(NULL);
	return CAIRO_INT_STATUS_SUCCESS;
    }

    int count = pixman_region_num_rects(region);
    pixman_box16_t* rects = pixman_region_rects(region);
    BRegion bregion;
    for (int i = 0; i < count; ++i) {
	// Have to substract one, because for pixman, the second coordinate
	// lies outside the rectangle.
	bregion.Include(BRect(rects[i].x1, rects[i].y1, rects[i].x2 - 1, rects[i].y2  - 1));
    }
    surface->view->ConstrainClippingRegion(&bregion);
    return CAIRO_INT_STATUS_SUCCESS;
}

static cairo_int_status_t
_cairo_beos_surface_get_extents (void				*abstract_surface,
				 cairo_rectangle_fixed_t	*rectangle)
{
    cairo_beos_surface_t *surface = reinterpret_cast<cairo_beos_surface_t*>(
							abstract_surface);
    AutoLockView locker(surface->view);
    if (!locker)
	return CAIRO_INT_STATUS_UNSUPPORTED;

    BRect size = surface->view->Bounds();

    *rectangle = _brect_to_cairo_rect(size);

    // Make sure to have our upperleft edge as (0,0)
    rectangle->x = 0;
    rectangle->y = 0;

    return CAIRO_INT_STATUS_SUCCESS;
}

static const struct _cairo_surface_backend cairo_beos_surface_backend = {
    CAIRO_SURFACE_TYPE_BEOS,
    _cairo_beos_surface_create_similar,
    _cairo_beos_surface_finish,
    _cairo_beos_surface_acquire_source_image,
    _cairo_beos_surface_release_source_image,
    _cairo_beos_surface_acquire_dest_image,
    _cairo_beos_surface_release_dest_image,
    NULL, /* clone_similar */
    _cairo_beos_surface_composite, /* composite */
    _cairo_beos_surface_fill_rectangles,
    NULL, /* composite_trapezoids */
    NULL, /* copy_page */
    NULL, /* show_page */
    _cairo_beos_surface_set_clip_region,
    NULL, /* intersect_clip_path */
    _cairo_beos_surface_get_extents,
    NULL,  /* old_show_glyphs */
    NULL, /* get_font_options */
    NULL, /* flush */
    NULL, /* mark_dirty_rectangle */
    NULL, /* scaled_font_fini */
    NULL, /* scaled_glyph_fini */

    NULL, /* paint */
    NULL, /* mask */
    NULL, /* stroke */
    NULL, /* fill */
    NULL  /* show_glyphs */
};

static cairo_surface_t *
_cairo_beos_surface_create_internal (BView*   view,
				     BBitmap* bmp,
				     bool     owns_bitmap_view)
{
    // Must use malloc, because cairo code will use free() on the surface
    cairo_beos_surface_t *surface = static_cast<cairo_beos_surface_t*>(
					malloc(sizeof(cairo_beos_surface_t)));
    if (surface == NULL) {
	_cairo_error (CAIRO_STATUS_NO_MEMORY);
        return const_cast<cairo_surface_t*>(&_cairo_surface_nil);
    }

    cairo_content_t content = CAIRO_CONTENT_COLOR;
    if (bmp && (bmp->ColorSpace() == B_RGBA32 || bmp->ColorSpace() == B_RGBA15))
	content = CAIRO_CONTENT_COLOR_ALPHA;
    _cairo_surface_init(&surface->base, &cairo_beos_surface_backend, content);

    surface->view = view;
    surface->bitmap = bmp;
    surface->owns_bitmap_view = owns_bitmap_view;

    return (cairo_surface_t *) surface;
}

/**
 * cairo_beos_surface_create:
 * @view: The view to draw on
 *
 * Creates a Cairo surface that draws onto a BeOS BView.
 * The caller must ensure that the view does not get deleted before the surface.
 * If the view is attached to a bitmap rather than an on-screen window, use
 * cairo_beos_surface_create_for_bitmap instead of this function.
 **/
cairo_surface_t *
cairo_beos_surface_create (BView* view)
{
    return cairo_beos_surface_create_for_bitmap(view, NULL);
}

/**
 * cairo_beos_surface_create_for_bitmap:
 * @view: The view to draw on
 * @bmp: The bitmap to which the view is attached
 *
 * Creates a Cairo surface that draws onto a BeOS BView which is attached to a
 * BBitmap.
 * The caller must ensure that the view and the bitmap do not get deleted
 * before the surface.
 *
 * For views that draw to a bitmap (as opposed to a screen), use this function
 * rather than cairo_beos_surface_create. Not using this function WILL lead to
 * incorrect behaviour.
 *
 * For now, only views that draw to the entire area of bmp are supported.
 * The view must already be attached to the bitmap.
 **/
cairo_surface_t *
cairo_beos_surface_create_for_bitmap (BView*   view,
				      BBitmap* bmp)
{
    return _cairo_beos_surface_create_internal(view, bmp);
}

// ---------------------------------------------------------------------------
// Cairo uses locks without explicit initialization. To support that, we
// provide a class here which manages the locks and is in global scope, so the
// compiler will instantiate it on library load and destroy it on library
// unload.

class BeLocks {
    public:
	BLocker cairo_toy_font_face_hash_table_mutex;
	BLocker cairo_scaled_font_map_mutex;
	BLocker cairo_ft_unscaled_font_map_mutex;
};

static BeLocks locks;

void* cairo_toy_font_face_hash_table_mutex = &locks.cairo_toy_font_face_hash_table_mutex;
void* cairo_scaled_font_map_mutex = &locks.cairo_scaled_font_map_mutex;
void* cairo_ft_unscaled_font_map_mutex = &locks.cairo_ft_unscaled_font_map_mutex;

void _cairo_beos_lock (void* locker) {
    BLocker* bLocker = reinterpret_cast<BLocker*>(locker);
    bLocker->Lock();
}

void _cairo_beos_unlock (void* locker) {
    BLocker* bLocker = reinterpret_cast<BLocker*>(locker);
    bLocker->Unlock();
}