cairo-win32-surface.c

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

}

static void
_cairo_win32_surface_release_source_image (void                   *abstract_surface,
					   cairo_image_surface_t  *image,
					   void                   *image_extra)
{
    cairo_win32_surface_t *local = image_extra;

    if (local)
	cairo_surface_destroy ((cairo_surface_t *)local);
}

static cairo_status_t
_cairo_win32_surface_acquire_dest_image (void                    *abstract_surface,
					 cairo_rectangle_int16_t *interest_rect,
					 cairo_image_surface_t  **image_out,
					 cairo_rectangle_int16_t *image_rect,
					 void                   **image_extra)
{
    cairo_win32_surface_t *surface = abstract_surface;
    cairo_win32_surface_t *local = NULL;
    cairo_status_t status;
    RECT clip_box;
    int x1, y1, x2, y2;

    if (surface->image) {
	GdiFlush();

	image_rect->x = 0;
	image_rect->y = 0;
	image_rect->width = surface->clip_rect.width;
	image_rect->height = surface->clip_rect.height;

	*image_out = (cairo_image_surface_t *)surface->image;
	*image_extra = NULL;

	return CAIRO_STATUS_SUCCESS;
    }

    if (GetClipBox (surface->dc, &clip_box) == ERROR)
	return _cairo_win32_print_gdi_error ("_cairo_win3_surface_acquire_dest_image");

    x1 = clip_box.left;
    x2 = clip_box.right;
    y1 = clip_box.top;
    y2 = clip_box.bottom;

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

    if (x1 >= x2 || y1 >= y2) {
	*image_out = NULL;
	*image_extra = NULL;

	return CAIRO_STATUS_SUCCESS;
    }

    status = _cairo_win32_surface_get_subimage (abstract_surface,
						x1, y1, x2 - x1, y2 - y1,
						&local);
    if (status)
	return status;

    *image_out = (cairo_image_surface_t *)local->image;
    *image_extra = local;

    image_rect->x = x1;
    image_rect->y = y1;
    image_rect->width = x2 - x1;
    image_rect->height = y2 - y1;

    return CAIRO_STATUS_SUCCESS;
}

static void
_cairo_win32_surface_release_dest_image (void                    *abstract_surface,
					 cairo_rectangle_int16_t *interest_rect,
					 cairo_image_surface_t   *image,
					 cairo_rectangle_int16_t *image_rect,
					 void                    *image_extra)
{
    cairo_win32_surface_t *surface = abstract_surface;
    cairo_win32_surface_t *local = image_extra;

    if (!local)
	return;

    if (!BitBlt (surface->dc,
		 image_rect->x, image_rect->y,
		 image_rect->width, image_rect->height,
		 local->dc,
		 0, 0,
		 SRCCOPY))
	_cairo_win32_print_gdi_error ("_cairo_win32_surface_release_dest_image");

    cairo_surface_destroy ((cairo_surface_t *)local);
}

#if !defined(AC_SRC_OVER)
#define AC_SRC_OVER                 0x00
#pragma pack(1)
typedef struct {
    BYTE   BlendOp;
    BYTE   BlendFlags;
    BYTE   SourceConstantAlpha;
    BYTE   AlphaFormat;
}BLENDFUNCTION;
#pragma pack()
#endif

/* for compatibility with VC++ 6 */
#ifndef AC_SRC_ALPHA
#define AC_SRC_ALPHA                0x01
#endif

typedef BOOL (WINAPI *cairo_alpha_blend_func_t) (HDC hdcDest,
						 int nXOriginDest,
						 int nYOriginDest,
						 int nWidthDest,
						 int hHeightDest,
						 HDC hdcSrc,
						 int nXOriginSrc,
						 int nYOriginSrc,
						 int nWidthSrc,
						 int nHeightSrc,
						 BLENDFUNCTION blendFunction);

static cairo_int_status_t
_composite_alpha_blend (cairo_win32_surface_t *dst,
			cairo_win32_surface_t *src,
			int                    alpha,
			int                    src_x,
			int                    src_y,
			int                    dst_x,
			int                    dst_y,
			int                    width,
			int                    height)
{
    static unsigned alpha_blend_checked = FALSE;
    static cairo_alpha_blend_func_t alpha_blend = NULL;

    BLENDFUNCTION blend_function;

    /* Check for AlphaBlend dynamically to allow compiling on
     * MSVC 6 and use on older windows versions
     */
    if (!alpha_blend_checked) {
	OSVERSIONINFO os;

	os.dwOSVersionInfoSize = sizeof (os);
	GetVersionEx (&os);

	/* If running on Win98, disable using AlphaBlend()
	 * to avoid Win98 AlphaBlend() bug */
	if (VER_PLATFORM_WIN32_WINDOWS != os.dwPlatformId ||
	    os.dwMajorVersion != 4 || os.dwMinorVersion != 10)
	{
	    HMODULE msimg32_dll = LoadLibrary ("msimg32");

	    if (msimg32_dll != NULL)
		alpha_blend = (cairo_alpha_blend_func_t)GetProcAddress (msimg32_dll,
									"AlphaBlend");
	}

	alpha_blend_checked = TRUE;
    }

    if (alpha_blend == NULL)
	return CAIRO_INT_STATUS_UNSUPPORTED;
    if (GetDeviceCaps(dst->dc, SHADEBLENDCAPS) == SB_NONE)
	return CAIRO_INT_STATUS_UNSUPPORTED;

    blend_function.BlendOp = AC_SRC_OVER;
    blend_function.BlendFlags = 0;
    blend_function.SourceConstantAlpha = alpha;
    blend_function.AlphaFormat = src->format == CAIRO_FORMAT_ARGB32 ? AC_SRC_ALPHA : 0;

    if (!alpha_blend (dst->dc,
		      dst_x, dst_y,
		      width, height,
		      src->dc,
		      src_x, src_y,
		      width, height,
		      blend_function))
	return _cairo_win32_print_gdi_error ("_cairo_win32_surface_composite");

    return CAIRO_STATUS_SUCCESS;
}

static cairo_int_status_t
_cairo_win32_surface_composite (cairo_operator_t	op,
				cairo_pattern_t       	*pattern,
				cairo_pattern_t		*mask_pattern,
				void			*abstract_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_win32_surface_t *dst = abstract_dst;
    cairo_win32_surface_t *src;
    cairo_surface_pattern_t *src_surface_pattern;
    int alpha;
    int integer_transform;
    int itx, ity;

    if (pattern->type != CAIRO_PATTERN_TYPE_SURFACE ||
	pattern->extend != CAIRO_EXTEND_NONE)
	return CAIRO_INT_STATUS_UNSUPPORTED;

    if (mask_pattern) {
	/* FIXME: When we fully support RENDER style 4-channel
	 * masks we need to check r/g/b != 1.0.
	 */
	if (mask_pattern->type != CAIRO_PATTERN_TYPE_SOLID)
	    return CAIRO_INT_STATUS_UNSUPPORTED;

	alpha = ((cairo_solid_pattern_t *)mask_pattern)->color.alpha_short >> 8;
    } else {
        alpha = 255;
    }

    src_surface_pattern = (cairo_surface_pattern_t *)pattern;
    src = (cairo_win32_surface_t *)src_surface_pattern->surface;

    if (src->base.backend != dst->base.backend)
	return CAIRO_INT_STATUS_UNSUPPORTED;

    integer_transform = _cairo_matrix_is_integer_translation (&pattern->matrix, &itx, &ity);
    if (!integer_transform)
	return CAIRO_INT_STATUS_UNSUPPORTED;

    /* Fix up src coordinates; the src coords and size must be within the
     * bounds of the source surface.
     * XXX the region not covered should be appropriately rendered!
     * - for OVER/SOURCE with RGB24 source -> opaque black
     * - for SOURCE with ARGB32 source -> 100% transparent black
     */
    src_x += itx;
    src_y += ity;

    if (src_x < 0) {
        width += src_x;
        dst_x -= src_x;
        src_x = 0;
    }

    if (src_y < 0) {
        height += src_y;
        dst_y -= src_y;
        src_y = 0;
    }

    if (src_x + width > src->extents.width)
        width = src->extents.width - src_x;

    if (src_y + height > src->extents.height)
        height = src->extents.height - src_y;

    if (alpha == 255 &&
	(op == CAIRO_OPERATOR_SOURCE ||
	 (src->format == CAIRO_FORMAT_RGB24 && op == CAIRO_OPERATOR_OVER))) {

	if (!BitBlt (dst->dc,
		     dst_x, dst_y,
		     width, height,
		     src->dc,
		     src_x, src_y,
		     SRCCOPY))
	    return _cairo_win32_print_gdi_error ("_cairo_win32_surface_composite");

	return CAIRO_STATUS_SUCCESS;

    } else if ((src->format == CAIRO_FORMAT_RGB24 || src->format == CAIRO_FORMAT_ARGB32) &&
	       (dst->format == CAIRO_FORMAT_RGB24 || dst->format == CAIRO_FORMAT_ARGB32) &&
	       op == CAIRO_OPERATOR_OVER) {

	return _composite_alpha_blend (dst, src, alpha,
				       src_x, src_y,
				       dst_x, dst_y, width, height);
    }

    return CAIRO_INT_STATUS_UNSUPPORTED;
}

/* This big function tells us how to optimize operators for the
 * case of solid destination and constant-alpha source
 *
 * NOTE: This function needs revisiting if we add support for
 *       super-luminescent colors (a == 0, r,g,b > 0)
 */
static enum { DO_CLEAR, DO_SOURCE, DO_NOTHING, DO_UNSUPPORTED }
categorize_solid_dest_operator (cairo_operator_t op,
				unsigned short   alpha)
{
    enum { SOURCE_TRANSPARENT, SOURCE_LIGHT, SOURCE_SOLID, SOURCE_OTHER } source;

    if (alpha >= 0xff00)
	source = SOURCE_SOLID;
    else if (alpha < 0x100)
	source = SOURCE_TRANSPARENT;
    else
	source = SOURCE_OTHER;

    switch (op) {
    case CAIRO_OPERATOR_CLEAR:    /* 0                 0 */
    case CAIRO_OPERATOR_OUT:      /* 1 - Ab            0 */
	return DO_CLEAR;
	break;

    case CAIRO_OPERATOR_SOURCE:   /* 1                 0 */
    case CAIRO_OPERATOR_IN:       /* Ab                0 */
	return DO_SOURCE;
	break;

    case CAIRO_OPERATOR_OVER:     /* 1            1 - Aa */
    case CAIRO_OPERATOR_ATOP:     /* Ab           1 - Aa */
	if (source == SOURCE_SOLID)
	    return DO_SOURCE;
	else if (source == SOURCE_TRANSPARENT)
	    return DO_NOTHING;
	else
	    return DO_UNSUPPORTED;
	break;

    case CAIRO_OPERATOR_DEST_OUT: /* 0            1 - Aa */
    case CAIRO_OPERATOR_XOR:      /* 1 - Ab       1 - Aa */
	if (source == SOURCE_SOLID)
	    return DO_CLEAR;
	else if (source == SOURCE_TRANSPARENT)
	    return DO_NOTHING;
	else
	    return DO_UNSUPPORTED;
    	break;

    case CAIRO_OPERATOR_DEST:     /* 0                 1 */
    case CAIRO_OPERATOR_DEST_OVER:/* 1 - Ab            1 */
    case CAIRO_OPERATOR_SATURATE: /* min(1,(1-Ab)/Aa)  1 */
	return DO_NOTHING;
	break;

    case CAIRO_OPERATOR_DEST_IN:  /* 0                Aa */
    case CAIRO_OPERATOR_DEST_ATOP:/* 1 - Ab           Aa */
	if (source == SOURCE_SOLID)
	    return DO_NOTHING;
	else if (source == SOURCE_TRANSPARENT)
	    return DO_CLEAR;
	else
	    return DO_UNSUPPORTED;
	break;

    case CAIRO_OPERATOR_ADD:	  /* 1                1 */
	if (source == SOURCE_TRANSPARENT)
	    return DO_NOTHING;
	else
	    return DO_UNSUPPORTED;
	break;
    }

    ASSERT_NOT_REACHED;
    return DO_UNSUPPORTED;
}

static cairo_int_status_t
_cairo_win32_surface_fill_rectangles (void			*abstract_surface,
				      cairo_operator_t		op,
				      const cairo_color_t	*color,
				      cairo_rectangle_int16_t		*rects,
				      int			num_rects)
{
    cairo_win32_surface_t *surface = abstract_surface;
    cairo_status_t status;
    COLORREF new_color;
    HBRUSH new_brush;
    int i;

    /* XXXperf If it's not RGB24, we need to do a little more checking
     * to figure out when we can use GDI.  We don't have that checking
     * anywhere at the moment, so just bail and use the fallback
     * paths. */
    if (surface->format != CAIRO_FORMAT_RGB24)
	return CAIRO_INT_STATUS_UNSUPPORTED;

    /* Optimize for no destination alpha (surface->pixman_image is non-NULL for all
     * surfaces with alpha.)
     */
    switch (categorize_solid_dest_operator (op, color->alpha_short)) {
    case DO_CLEAR:
	new_color = RGB (0, 0, 0);
	break;
    case DO_SOURCE:
	new_color = RGB (color->red_short >> 8, color->green_short >> 8, color->blue_short >> 8);
	break;
    case DO_NOTHING:
	return CAIRO_STATUS_SUCCESS;
    case DO_UNSUPPORTED:
    default:
	return CAIRO_INT_STATUS_UNSUPPORTED;
    }

    new_brush = CreateSolidBrush (new_color);
    if (!new_brush)
	return _cairo_win32_print_gdi_error ("_cairo_win32_surface_fill_rectangles");

    for (i = 0; i < num_rects; i++) {
	RECT rect;

	rect.left = rects[i].x;
	rect.top = rects[i].y;
	rect.right = rects[i].x + rects[i].width;
	rect.bottom = rects[i].y + rects[i].height;

	if (!FillRect (surface->dc, &rect, new_brush))
	    goto FAIL;
    }

    DeleteObject (new_brush);

    return CAIRO_STATUS_SUCCESS;

 FAIL:
    status = _cairo_win32_print_gdi_error ("_cairo_win32_surface_fill_rectangles");

    DeleteObject (new_brush);