src/guacenc/buffer.h

/*
 * 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.
 */

#ifndef GUACENC_BUFFER_H
#define GUACENC_BUFFER_H

#include "config.h"

#include <cairo/cairo.h>

#include <stdbool.h>

/**
 * The image and size storage for either a buffer (a Guacamole layer with a
 * negative index) or a layer (a Guacamole layer with a non-negative index).
 */
typedef struct guacenc_buffer {

    /**
     * Whether this buffer should be automatically resized to fit any draw
     * operation.
     */
    bool autosize;

    /**
     * The width of this buffer or layer, in pixels.
     */
    int width;

    /**
     * The height of this buffer or layer, in pixels.
     */
    int height;

    /**
     * The number of bytes in each row of image data.
     */
    int stride;

    /**
     * The underlying image data of this surface. If the width or height of
     * this surface are 0, this will be NULL.
     */
    unsigned char* image;

    /**
     * The Cairo surface wrapping the underlying image data of this surface. If
     * the width or height of this surface are 0, this will be NULL.
     */
    cairo_surface_t* surface;

    /**
     * The current graphics context of the Cairo surface. If the width or
     * height of this surface are 0, this will be NULL.
     */
    cairo_t* cairo;

} guacenc_buffer;

/**
 * Allocates and initializes a new buffer object. This allocation is
 * independent of the Guacamole video encoder display; the allocated
 * guacenc_buffer will not automatically be associated with the active display.
 *
 * @return
 *     A newly-allocated and initialized guacenc_buffer, or NULL if allocation
 *     fails.
 */
guacenc_buffer* guacenc_buffer_alloc();

/**
 * Frees all memory associated with the given buffer object. If the buffer
 * provided is NULL, this function has no effect.
 *
 * @param buffer
 *     The buffer to free, which may be NULL.
 */
void guacenc_buffer_free(guacenc_buffer* buffer);

/**
 * Resizes the given buffer to the given dimensions, allocating or freeing
 * memory as necessary, and updating the buffer's width, height, and stride
 * properties.
 *
 * @param buffer
 *     The buffer to resize.
 *
 * @param width
 *     The new width of the buffer, in pixels.
 *
 * @param height
 *     The new height of the buffer, in pixels.
 *
 * @return
 *     Zero if the resize operation is successful, non-zero on error.
 */
int guacenc_buffer_resize(guacenc_buffer* buffer, int width, int height);

/**
 * Resizes the given buffer as necessary to contain at the given X/Y
 * coordinate, allocating or freeing memory as necessary, and updating the
 * buffer's width, height, and stride properties. If the buffer already
 * contains the given coordinate, this function has no effect.
 *
 * @param buffer
 *     The buffer to resize.
 *
 * @param x
 *     The X coordinate to ensure is within the buffer.
 *
 * @param y
 *     The Y coordinate to ensure is within the buffer.
 *
 * @return
 *     Zero if the resize operation is successful or no resize was performed,
 *     non-zero if the resize operation failed.
 */
int guacenc_buffer_fit(guacenc_buffer* buffer, int x, int y);

/**
 * Copies the entire contents of the given source buffer to the destination
 * buffer, ignoring the current contents of the destination. The destination
 * buffer's contents are entirely replaced.
 *
 * @param dst
 *     The destination buffer whose contents should be replaced.
 *
 * @param src
 *     The source buffer whose contents should replace those of the destination
 *     buffer.
 *
 * @return
 *     Zero if the copy operation was successful, non-zero on failure.
 */
int guacenc_buffer_copy(guacenc_buffer* dst, guacenc_buffer* src);

#endif