guacamole-spice-protocol/src/guacenc/display-flatten.c
2016-03-28 20:39:19 -07:00

158 lines
4.8 KiB
C

/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
#include "config.h"
#include "display.h"
#include "layer.h"
#include <cairo/cairo.h>
#include <stdlib.h>
#include <string.h>
/**
* The Guacamole video encoder display related to the current qsort()
* operation. As qsort() does not provide a means of passing arbitrary data to
* the comparitor, this value must be set prior to invoking qsort() with
* guacenc_display_layer_comparator.
*/
guacenc_display* __qsort_display;
/**
* Comparator which orders layer pointers such that (1) NULL pointers are last,
* (2) layers with the same parent_index are adjacent, and (3) layers with the
* same parent_index are ordered by Z.
*
* @see qsort()
*/
static int guacenc_display_layer_comparator(const void* a, const void* b) {
guacenc_layer* layer_a = *((guacenc_layer**) a);
guacenc_layer* layer_b = *((guacenc_layer**) b);
/* If a is NULL, sort it to bottom */
if (layer_a == NULL) {
/* ... unless b is also NULL, in which case they are equal */
if (layer_b == NULL)
return 0;
return 1;
}
/* If b is NULL (and a is not NULL), sort it to bottom */
if (layer_b == NULL)
return -1;
/* Order such that the deepest layers are first */
int a_depth = guacenc_display_get_depth(__qsort_display, layer_a);
int b_depth = guacenc_display_get_depth(__qsort_display, layer_b);
if (b_depth != a_depth)
return b_depth - a_depth;
/* Order such that sibling layers are adjacent */
if (layer_b->parent_index != layer_a->parent_index)
return layer_b->parent_index - layer_a->parent_index;
/* Order sibling layers according to descending Z */
return layer_b->z - layer_a->z;
}
int guacenc_display_flatten(guacenc_display* display) {
int i;
guacenc_layer* render_order[GUACENC_DISPLAY_MAX_LAYERS];
/* Copy list of layers within display */
memcpy(render_order, display->layers, sizeof(render_order));
/* Sort layers by depth, parent, and Z */
__qsort_display = display;
qsort(render_order, GUACENC_DISPLAY_MAX_LAYERS, sizeof(guacenc_layer*),
guacenc_display_layer_comparator);
/* Reset layer frame buffers */
for (i = 0; i < GUACENC_DISPLAY_MAX_LAYERS; i++) {
/* Pull current layer, ignoring unallocated layers */
guacenc_layer* layer = render_order[i];
if (layer == NULL)
continue;
/* Get source buffer and destination frame buffer */
guacenc_buffer* buffer = layer->buffer;
guacenc_buffer* frame = layer->frame;
/* Reset frame contents */
guacenc_buffer_copy(frame, buffer);
}
/* Render each layer, in order */
for (i = 0; i < GUACENC_DISPLAY_MAX_LAYERS; i++) {
/* Pull current layer, ignoring unallocated layers */
guacenc_layer* layer = render_order[i];
if (layer == NULL)
continue;
/* Skip fully-transparent layers */
if (layer->opacity == 0)
continue;
/* Ignore layers without a parent */
int parent_index = layer->parent_index;
if (parent_index == GUACENC_LAYER_NO_PARENT)
continue;
/* Retrieve parent layer, ignoring layers with invalid parents */
guacenc_layer* parent = guacenc_display_get_layer(display, parent_index);
if (parent == NULL)
continue;
/* Get source and destination frame buffer */
guacenc_buffer* src = layer->frame;
guacenc_buffer* dst = parent->frame;
/* Ignore layers with empty buffers */
cairo_surface_t* surface = src->surface;
if (surface == NULL)
continue;
/* Ignore if parent has no pixels */
cairo_t* cairo = dst->cairo;
if (cairo == NULL)
continue;
/* Render buffer to layer */
cairo_reset_clip(cairo);
cairo_rectangle(cairo, layer->x, layer->y, src->width, src->height);
cairo_clip(cairo);
cairo_set_source_surface(cairo, surface, layer->x, layer->y);
cairo_paint_with_alpha(cairo, layer->opacity / 255.0);
}
return 0;
}