src/common/guac_surface.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 __GUAC_COMMON_SURFACE_H
#define __GUAC_COMMON_SURFACE_H

#include "config.h"
#include "guac_rect.h"

#include <cairo/cairo.h>
#include <guacamole/client.h>
#include <guacamole/layer.h>
#include <guacamole/protocol.h>
#include <guacamole/socket.h>

/**
 * The maximum number of updates to allow within the bitmap queue.
 */
#define GUAC_COMMON_SURFACE_QUEUE_SIZE 256

/**
 * Heat map cell size in pixels. Each side of each heat map cell will consist
 * of this many pixels.
 */
#define GUAC_COMMON_SURFACE_HEAT_CELL_SIZE 64

/**
 * The width or height of the heat map (in cells) given the width or height of
 * the image (in pixels).
 */
#define GUAC_COMMON_SURFACE_HEAT_DIMENSION(x) (       \
        (x + GUAC_COMMON_SURFACE_HEAT_CELL_SIZE - 1)  \
            / GUAC_COMMON_SURFACE_HEAT_CELL_SIZE      \
)

/**
 * The number of entries to collect within each heat map cell. Collected
 * history entries are used to determine the framerate of the region associated
 * with that cell.
 */
#define GUAC_COMMON_SURFACE_HEAT_CELL_HISTORY_SIZE 5

/**
 * Representation of a cell in the refresh heat map. This cell is used to keep
 * track of how often an area on a surface is refreshed.
 */
typedef struct guac_common_surface_heat_cell {

    /**
     * Timestamps of each of the last N updates covering the location
     * associated with this heat map cell. This is used to calculate the
     * framerate. This array is structured as a ring buffer containing history
     * entries in chronologically-ascending order, starting at the entry
     * pointed to by oldest_entry and proceeding through all other entries,
     * wrapping around if the end of the array is reached.
     */
    guac_timestamp history[GUAC_COMMON_SURFACE_HEAT_CELL_HISTORY_SIZE];

    /**
     * Index of the oldest entry within the history.
     */
    int oldest_entry;

} guac_common_surface_heat_cell;

/**
 * Representation of a bitmap update, having a rectangle of image data (stored
 * elsewhere) and a flushed/not-flushed state.
 */
typedef struct guac_common_surface_bitmap_rect {

    /**
     * Whether this rectangle has been flushed.
     */
    int flushed;

    /**
     * The rectangle containing the bitmap update.
     */
    guac_common_rect rect;

} guac_common_surface_bitmap_rect;

/**
 * Surface which backs a Guacamole buffer or layer, automatically
 * combining updates when possible.
 */
typedef struct guac_common_surface {

    /**
     * The layer this surface will draw to.
     */
    const guac_layer* layer;

    /**
     * The client associated with this surface.
     */
    guac_client* client;

    /**
     * The socket to send instructions on when flushing.
     */
    guac_socket* socket;

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

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

    /**
     * The size of each image row, in bytes.
     */
    int stride;

    /**
     * The underlying buffer of the Cairo surface.
     */
    unsigned char* buffer;

    /**
     * Non-zero if this surface is dirty and needs to be flushed, 0 otherwise.
     */
    int dirty;

    /**
     * The dirty rectangle.
     */
    guac_common_rect dirty_rect;

    /**
     * Whether the surface actually exists on the client.
     */
    int realized;

    /**
     * Whether drawing operations are currently clipped by the clipping
     * rectangle.
     */
    int clipped;

    /**
     * The clipping rectangle.
     */
    guac_common_rect clip_rect;

    /**
     * The number of updates in the bitmap queue.
     */
    int bitmap_queue_length;

    /**
     * All queued bitmap updates.
     */
    guac_common_surface_bitmap_rect bitmap_queue[GUAC_COMMON_SURFACE_QUEUE_SIZE];

    /**
     * A heat map keeping track of the refresh frequency of
     * the areas of the screen.
     */
    guac_common_surface_heat_cell* heat_map;

} guac_common_surface;

/**
 * Allocates a new guac_common_surface, assigning it to the given layer.
 *
 * @param client
 *     The client associated with the given layer.
 *
 * @param socket
 *     The socket to send instructions on when flushing.
 *
 * @param layer
 *     The layer to associate with the new surface.
 *
 * @param w
 *     The width of the surface.
 *
 * @param h
 *     The height of the surface.
 *
 * @return
 *     A newly-allocated guac_common_surface.
 */
guac_common_surface* guac_common_surface_alloc(guac_client* client,
        guac_socket* socket, const guac_layer* layer, int w, int h);

/**
 * Frees the given guac_common_surface. Beware that this will NOT free any
 * associated layers, which must be freed manually.
 *
 * @param surface The surface to free.
 */
void guac_common_surface_free(guac_common_surface* surface);

 /**
 * Resizes the given surface to the given size.
 *
 * @param surface The surface to resize.
 * @param w The width of the surface.
 * @param h The height of the surface.
 */
void guac_common_surface_resize(guac_common_surface* surface, int w, int h);

/**
 * Draws the given data to the given guac_common_surface.
 *
 * @param surface The surface to draw to.
 * @param x The X coordinate of the draw location.
 * @param y The Y coordinate of the draw location.
 * @param src The Cairo surface to retrieve data from.
 */
void guac_common_surface_draw(guac_common_surface* surface, int x, int y, cairo_surface_t* src);

/**
 * Paints to the given guac_common_surface using the given data as a stencil,
 * filling opaque regions with the specified color, and leaving transparent
 * regions untouched.
 *
 * @param surface The surface to draw to.
 * @param x The X coordinate of the draw location.
 * @param y The Y coordinate of the draw location.
 * @param src The Cairo surface to retrieve data from.
 * @param red The red component of the fill color.
 * @param green The green component of the fill color.
 * @param blue The blue component of the fill color.
 */
void guac_common_surface_paint(guac_common_surface* surface, int x, int y, cairo_surface_t* src,
                              int red, int green, int blue);

/**
 * Copies a rectangle of data between two surfaces.
 *
 * @param src The source surface.
 * @param sx The X coordinate of the upper-left corner of the source rect.
 * @param sy The Y coordinate of the upper-left corner of the source rect.
 * @param w The width of the source rect.
 * @param h The height of the source rect.
 * @param dst The destination surface.
 * @param dx The X coordinate of the upper-left corner of the destination rect.
 * @param dy The Y coordinate of the upper-left corner of the destination rect.
 */
void guac_common_surface_copy(guac_common_surface* src, int sx, int sy, int w, int h,
                              guac_common_surface* dst, int dx, int dy);

/**
 * Transfers a rectangle of data between two surfaces.
 *
 * @param src The source surface.
 * @param sx The X coordinate of the upper-left corner of the source rect.
 * @param sy The Y coordinate of the upper-left corner of the source rect.
 * @param w The width of the source rect.
 * @param h The height of the source rect.
 * @param op The transfer function.
 * @param dst The destination surface.
 * @param dx The X coordinate of the upper-left corner of the destination rect.
 * @param dy The Y coordinate of the upper-left corner of the destination rect.
 */
void guac_common_surface_transfer(guac_common_surface* src, int sx, int sy, int w, int h,
                                  guac_transfer_function op, guac_common_surface* dst, int dx, int dy);

/**
 * Draws a solid color rectangle at the given coordinates on the given surface.
 *
 * @param surface The surface to draw upon.
 * @param x The X coordinate of the upper-left corner of the rectangle.
 * @param y The Y coordinate of the upper-left corner of the rectangle.
 * @param w The width of the rectangle.
 * @param h The height of the rectangle.
 * @param red The red component of the color of the rectangle.
 * @param green The green component of the color of the rectangle.
 * @param blue The blue component of the color of the rectangle.
 */
void guac_common_surface_rect(guac_common_surface* surface,
                              int x, int y, int w, int h,
                              int red, int green, int blue);

/**
 * Given the coordinates and dimensions of a rectangle, clips all future
 * operations within that rectangle.
 *
 * @param surface The surface whose clipping rectangle should be changed.
 * @param x The X coordinate of the upper-left corner of the bounding rectangle.
 * @param y The Y coordinate of the upper-left corner of the bounding rectangle.
 * @param w The width of the bounding rectangle.
 * @param h The height of the bounding rectangle.
 */
void guac_common_surface_clip(guac_common_surface* surface, int x, int y, int w, int h);

/**
 * Resets the clipping rectangle, allowing drawing operations throughout the
 * entire surface.
 *
 * @param surface The surface whose clipping rectangle should be reset.
 */
void guac_common_surface_reset_clip(guac_common_surface* surface);

/**
 * Flushes the given surface, drawing any pending operations on the remote
 * display.
 *
 * @param surface The surface to flush.
 */
void guac_common_surface_flush(guac_common_surface* surface);

/**
 * Schedules a deferred flush of the given surface. This will not immediately
 * flush the surface to the client. Instead, the result of the flush is
 * added to a queue which is reinspected and combined (if possible) with other
 * deferred flushes during the call to guac_common_surface_flush().
 *
 * @param surface The surface to flush.
 */
void guac_common_surface_flush_deferred(guac_common_surface* surface);

/**
 * Duplicates the contents of the current surface to the given socket. Pending
 * changes are not flushed.
 *
 * @param surface
 *     The surface to duplicate.
 *
 * @param user
 *     The user receiving the surface.
 *
 * @param socket
 *     The socket over which the surface contents should be sent.
 */
void guac_common_surface_dup(guac_common_surface* surface, guac_user* user,
        guac_socket* socket);

#endif