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/*
* art_render_mask.c: Alpha mask source for modular rendering.
*
* Libart_LGPL - library of basic graphic primitives
* Copyright (C) 2000 Raph Levien
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 3 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
* Boston, MA 02111-1307, USA.
*
* Authors: Raph Levien <raph@acm.org>
*/
#include "config.h"
#include "art_render_mask.h"
#include <string.h>
typedef struct _ArtMaskSourceMask ArtMaskSourceMask;
struct _ArtMaskSourceMask {
ArtMaskSource super;
ArtRender *render;
art_boolean first;
int x0;
int y0;
int x1;
int y1;
const art_u8 *mask_buf;
int rowstride;
};
static void
art_render_mask_done (ArtRenderCallback *self, ArtRender *render)
{
art_free (self);
}
static int
art_render_mask_can_drive (ArtMaskSource *self, ArtRender *render)
{
return 0;
}
static void
art_render_mask_render (ArtRenderCallback *self, ArtRender *render,
art_u8 *dest, int y)
{
ArtMaskSourceMask *z = (ArtMaskSourceMask *)self;
int x0 = render->x0, x1 = render->x1;
int z_x0 = z->x0, z_x1 = z->x1;
int width = x1 - x0;
int z_width = z_x1 - z_x0;
art_u8 *alpha_buf = render->alpha_buf;
if (y < z->y0 || y >= z->y1 || z_width <= 0)
memset (alpha_buf, 0, width);
else
{
const art_u8 *src_line = z->mask_buf + (y - z->y0) * z->rowstride;
art_u8 *dst_line = alpha_buf + z_x0 - x0;
if (z_x0 > x0)
memset (alpha_buf, 0, z_x0 - x0);
if (z->first)
memcpy (dst_line, src_line, z_width);
else
{
int x;
for (x = 0; x < z_width; x++)
{
int v;
v = src_line[x];
if (v)
{
v = v * dst_line[x] + 0x80;
v = (v + (v >> 8)) >> 8;
dst_line[x] = v;
}
else
{
dst_line[x] = 0;
}
}
}
if (z_x1 < x1)
memset (alpha_buf + z_x1 - x0, 0, x1 - z_x1);
}
}
static void
art_render_mask_prepare (ArtMaskSource *self, ArtRender *render,
art_boolean first)
{
ArtMaskSourceMask *z = (ArtMaskSourceMask *)self;
self->super.render = art_render_mask_render;
z->first = first;
}
/**
* art_render_mask: Use an alpha buffer as a render mask source.
* @render: Render object.
* @x0: Left coordinate of mask rect.
* @y0: Top coordinate of mask rect.
* @x1: Right coordinate of mask rect.
* @y1: Bottom coordinate of mask rect.
* @mask_buf: Buffer containing 8bpp alpha mask data.
* @rowstride: Rowstride of @mask_buf.
*
* Adds @mask_buf to the render object as a mask. Note: @mask_buf must
* remain allocated until art_render_invoke() is called on @render.
**/
void
art_render_mask (ArtRender *render,
int x0, int y0, int x1, int y1,
const art_u8 *mask_buf, int rowstride)
{
ArtMaskSourceMask *mask_source;
if (x0 < render->x0)
{
mask_buf += render->x0 - x0;
x0 = render->x0;
}
if (x1 > render->x1)
x1 = render->x1;
if (y0 < render->y0)
{
mask_buf += (render->y0 - y0) * rowstride;
y0 = render->y0;
}
if (y1 > render->y1)
y1 = render->y1;
mask_source = art_new (ArtMaskSourceMask, 1);
mask_source->super.super.render = NULL;
mask_source->super.super.done = art_render_mask_done;
mask_source->super.can_drive = art_render_mask_can_drive;
mask_source->super.invoke_driver = NULL;
mask_source->super.prepare = art_render_mask_prepare;
mask_source->render = render;
mask_source->x0 = x0;
mask_source->y0 = y0;
mask_source->x1 = x1;
mask_source->y1 = y1;
mask_source->mask_buf = mask_buf;
mask_source->rowstride = rowstride;
art_render_add_mask_source (render, &mask_source->super);
}
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