Merge pull request #86 from glyptodon/webp-support

GUAC-1305: Add support for WebP

configure.ac

@@ -931,6 +931,40 @@ AM_CONDITIONAL([ENABLE_TELNET], [test "x${have_libtelnet}"  = "xyes" \
 
 AC_SUBST(TELNET_LIBS)
 
+#
+# libwebp
+#
+
+have_webp=disabled
+WEBP_LIBS=
+AC_ARG_WITH([webp],
+            [AS_HELP_STRING([--with-webp],
+                            [support WebP image encoding @<:@default=check@:>@])],
+            [],
+            [with_webp=check])
+
+if test "x$with_webp" != "xno"
+then
+    have_webp=yes
+
+    AC_CHECK_HEADER(webp/encode.h,, [have_webp=no])
+    AC_CHECK_LIB([webp], [WebPEncode], [WEBP_LIBS="$WEBP_LIBS -lwebp"], [have_webp=no])
+
+    if test "x${have_webp}" = "xno"
+    then
+        AC_MSG_WARN([
+  --------------------------------------------
+   Unable to find libwebp.
+   Images will not be encoded using WebP.
+  --------------------------------------------])
+    else
+        AC_DEFINE([ENABLE_WEBP],, [Whether WebP support is enabled])
+    fi
+fi
+
+AM_CONDITIONAL([ENABLE_WEBP], [test "x${have_webp}" = "xyes"])
+AC_SUBST(WEBP_LIBS)
+
 
 AC_CONFIG_FILES([Makefile
                  tests/Makefile
@@ -967,6 +1001,7 @@ $PACKAGE_NAME version $PACKAGE_VERSION
      libVNCServer ........ ${have_libvncserver}
      libvorbis ........... ${have_vorbis}
      libpulse ............ ${have_pulse}
+     libwebp ............. ${have_webp}
 
    Protocol support:
 

src/common/guac_surface.c

@@ -91,6 +91,13 @@
  */
 #define GUAC_COMMON_SURFACE_JPEG_FRAMERATE 3
 
+/**
+ * The WebP image quality ('quantization') setting to use. Range 0-100 where
+ * 100 is the highest quality/largest file size, and 0 is the lowest
+ * quality/smallest file size.
+ */
+#define GUAC_SURFACE_WEBP_IMAGE_QUALITY 90
+
 /**
  * Updates the coordinates of the given rectangle to be within the bounds of
  * the given surface.
@@ -314,8 +321,9 @@ static unsigned int __guac_common_surface_calculate_framerate(
 
  /**
  * Guesses whether a rectangle within a particular surface would be better
- * compressed as PNG or as JPEG. Positive values indicate PNG is likely to
+ * compressed as PNG or using a lossy format like JPEG. Positive values
- * be superior, while negative values indicate JPEG.
+ * indicate PNG is likely to be superior, while negative values indicate the
+ * opposite.
  *
  * @param surface
  *     The surface containing the image data to check.
@@ -325,7 +333,8 @@ static unsigned int __guac_common_surface_calculate_framerate(
  *
  * @return
  *     Positive values if PNG compression is likely to perform better than
- *     JPEG, or negative values if JPEG is likely to perform better than PNG.
+ *     lossy alternatives, or negative values if PNG is likely to perform
+ *     worse.
  */
 static int __guac_common_surface_png_optimality(guac_common_surface* surface,
         const guac_common_rect* rect) {
@@ -405,6 +414,32 @@ static int __guac_common_surface_should_use_jpeg(guac_common_surface* surface,
 
 }
 
+/**
+ * Returns whether the given rectangle would be optimally encoded as WebP 
+ * rather than PNG.
+ *
+ * @param surface
+ *     The surface to be queried.
+ *
+ * @param rect
+ *     The rectangle to check.
+ *
+ * @return
+ *     Non-zero if the rectangle would be optimally encoded as WebP, zero
+ *     otherwise.
+ */
+static int __guac_common_surface_should_use_webp(guac_common_surface* surface,
+        const guac_common_rect* rect) {
+
+    /* Do not use WebP if not supported */
+    if (!guac_client_supports_webp(surface->client))
+        return 0;
+
+    /* Usage criteria are currently the same as JPEG */
+    return __guac_common_surface_should_use_jpeg(surface, rect);
+
+}
+
 /**
  * Updates the heat map cells which intersect the given rectangle using the
  * given timestamp. This timestamp, along with timestamps from past updates,
@@ -1276,6 +1311,47 @@ static void __guac_common_surface_flush_to_jpeg(guac_common_surface* surface) {
 
 }
 
+/**
+ * Flushes the bitmap update currently described by the dirty rectangle within
+ * the given surface directly via an "img" instruction as WebP data. The
+ * resulting instructions will be sent over the socket associated with the
+ * given surface.
+ *
+ * @param surface
+ *     The surface to flush.
+ */
+static void __guac_common_surface_flush_to_webp(guac_common_surface* surface) {
+
+    if (surface->dirty) {
+
+        guac_socket* socket = surface->socket;
+        const guac_layer* layer = surface->layer;
+
+        /* Get Cairo surface for specified rect */
+        unsigned char* buffer = surface->buffer
+            + surface->dirty_rect.y * surface->stride
+            + surface->dirty_rect.x * 4;
+
+        cairo_surface_t* rect = cairo_image_surface_create_for_data(buffer,
+                CAIRO_FORMAT_RGB24,
+                surface->dirty_rect.width, surface->dirty_rect.height,
+                surface->stride);
+
+        /* Send WebP for rect */
+        guac_client_stream_webp(surface->client, socket, GUAC_COMP_OVER, layer,
+                surface->dirty_rect.x, surface->dirty_rect.y, rect,
+                GUAC_SURFACE_WEBP_IMAGE_QUALITY);
+        cairo_surface_destroy(rect);
+        surface->realized = 1;
+
+        /* Surface is no longer dirty */
+        surface->dirty = 0;
+
+    }
+
+}
+
+
 /**
  * Comparator for instances of guac_common_surface_bitmap_rect, the elements
  * which make up a surface's bitmap buffer.
@@ -1357,12 +1433,17 @@ void guac_common_surface_flush(guac_common_surface* surface) {
 
                 flushed++;
 
-                /* Flush as JPEG if JPEG is preferred */
+                /* Prefer WebP when reasonable */
-                if (__guac_common_surface_should_use_jpeg(surface,
+                if (__guac_common_surface_should_use_webp(surface,
+                            &surface->dirty_rect))
+                    __guac_common_surface_flush_to_webp(surface);
+
+                /* If not WebP, JPEG is the next best (lossy) choice */
+                else if (__guac_common_surface_should_use_jpeg(surface,
                             &surface->dirty_rect))
                     __guac_common_surface_flush_to_jpeg(surface);
 
-                /* Otherwise, use PNG */
+                /* Use PNG if no lossy formats are appropriate */
                 else
                     __guac_common_surface_flush_to_png(surface);
 

src/libguac/Makefile.am

@@ -95,6 +95,13 @@ libguac_la_SOURCES += ogg_encoder.c
 noinst_HEADERS += ogg_encoder.h
 endif
 
+# Compile WebP support if available
+if ENABLE_WEBP
+libguac_la_SOURCES += encode-webp.c
+noinst_HEADERS += encode-webp.h
+endif
+
+
 libguac_la_CFLAGS = \
     -Werror -Wall -pedantic -Iguacamole
 
@@ -105,7 +112,8 @@ libguac_la_LDFLAGS =     \
     @PNG_LIBS@           \
     @PTHREAD_LIBS@       \
     @UUID_LIBS@          \
-    @VORBIS_LIBS@
+    @VORBIS_LIBS@        \
+    @WEBP_LIBS@
 
 libguac_la_LIBADD = \
     @LIBADD_DLOPEN@ 

src/libguac/client.c

@@ -36,6 +36,10 @@
 #include "stream.h"
 #include "timestamp.h"
 
+#ifdef ENABLE_WEBP
+#include "encode-webp.h"
+#endif
+
 #ifdef HAVE_OSSP_UUID_H
 #include <ossp/uuid.h>
 #else
@@ -419,3 +423,54 @@ void guac_client_stream_jpeg(guac_client* client, guac_socket* socket,
 
 }
 
+void guac_client_stream_webp(guac_client* client, guac_socket* socket,
+        guac_composite_mode mode, const guac_layer* layer, int x, int y,
+        cairo_surface_t* surface, int quality) {
+
+#ifdef ENABLE_WEBP
+    /* Allocate new stream for image */
+    guac_stream* stream = guac_client_alloc_stream(client);
+
+    /* Declare stream as containing image data */
+    guac_protocol_send_img(socket, stream, mode, layer, "image/webp", x, y);
+
+    /* Write WebP data */
+    guac_webp_write(socket, stream, surface, quality);
+
+    /* Terminate stream */
+    guac_protocol_send_end(socket, stream);
+
+    /* Free allocated stream */
+    guac_client_free_stream(client, stream);
+#else
+    /* Do nothing if WebP support is not built in */
+#endif
+
+}
+
+int guac_client_supports_webp(guac_client* client) {
+
+#ifdef ENABLE_WEBP
+    const char** mimetype = client->info.image_mimetypes;
+
+    /* Search for WebP mimetype in list of supported image mimetypes */
+    while (*mimetype != NULL) {
+
+        /* If WebP mimetype found, no need to search further */
+        if (strcmp(*mimetype, "image/webp") == 0)
+            return 1;
+
+        /* Next mimetype */
+        mimetype++;
+
+    }
+
+    /* Client does not support WebP */
+    return 0;
+#else
+    /* Support for WebP is completely absent */
+    return 0;
+#endif
+
+}
+

src/libguac/encode-webp.c

@@ -0,0 +1,261 @@
+/*
+ * Copyright (C) 2015 Glyptodon LLC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "config.h"
+
+#include "encode-webp.h"
+#include "error.h"
+#include "palette.h"
+#include "protocol.h"
+#include "stream.h"
+
+#include <cairo/cairo.h>
+#include <webp/encode.h>
+
+#include <assert.h>
+#include <inttypes.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+/**
+ * Structure which describes the current state of the WebP image writer.
+ */
+typedef struct guac_webp_stream_writer {
+
+    /**
+     * The socket over which all WebP blobs will be written.
+     */
+    guac_socket* socket;
+
+    /**
+     * The Guacamole stream to associate with each WebP blob.
+     */
+    guac_stream* stream;
+
+    /**
+     * Buffer of pending WebP data.
+     */
+    char buffer[6048];
+
+    /**
+     * The number of bytes currently stored in the buffer.
+     */
+    int buffer_size;
+
+} guac_webp_stream_writer;
+
+/**
+ * Writes the contents of the WebP stream writer as a blob to its associated
+ * socket.
+ *
+ * @param writer
+ *     The writer structure to flush.
+ */
+static void guac_webp_flush_data(guac_webp_stream_writer* writer) {
+
+    /* Send blob */
+    guac_protocol_send_blob(writer->socket, writer->stream,
+            writer->buffer, writer->buffer_size);
+
+    /* Clear buffer */
+    writer->buffer_size = 0;
+
+}
+
+/**
+ * Configures the given stream writer object to use the given Guacamole stream
+ * object for WebP output.
+ *
+ * @param writer
+ *     The Guacamole WebP stream writer structure to configure.
+ *
+ * @param socket
+ *     The Guacamole socket to use when sending blob instructions.
+ *
+ * @param stream
+ *     The stream over which WebP-encoded blobs of image data should be sent.
+ */
+static void guac_webp_stream_writer_init(guac_webp_stream_writer* writer,
+        guac_socket* socket, guac_stream* stream) {
+
+    writer->buffer_size = 0;
+
+    /* Store Guacamole-specific objects */
+    writer->socket = socket;
+    writer->stream = stream;
+
+}
+
+/**
+ * WebP output function which appends the given WebP data to the internal
+ * buffer of the Guacamole stream writer structure, automatically flushing the
+ * writer as necessary.
+ *
+ * @param data
+ *     The segment of data to write.
+ *
+ * @param data_size
+ *     The size of segment of data to write.
+ *
+ * @param picture
+ *     The WebP picture associated with this write operation. Provides access to
+ *     picture->custom_ptr which contains the Guacamole stream writer structure.
+ *
+ * @return
+ *     Non-zero if writing was successful, zero on failure.
+ */
+static int guac_webp_stream_write(const uint8_t* data, size_t data_size,
+        const WebPPicture* picture) {
+
+    guac_webp_stream_writer* const writer =
+        (guac_webp_stream_writer*) picture->custom_ptr;
+    assert(writer != NULL);
+
+    const unsigned char* current = data;
+    int length = data_size;
+
+    /* Append all data given */
+    while (length > 0) {
+
+        /* Calculate space remaining */
+        int remaining = sizeof(writer->buffer) - writer->buffer_size;
+
+        /* If no space remains, flush buffer to make room */
+        if (remaining == 0) {
+            guac_webp_flush_data(writer);
+            remaining = sizeof(writer->buffer);
+        }
+
+        /* Calculate size of next block of data to append */
+        int block_size = remaining;
+        if (block_size > length)
+            block_size = length;
+
+        /* Append block */
+        memcpy(writer->buffer + writer->buffer_size,
+               current, block_size);
+
+        /* Next block */
+        current += block_size;
+        writer->buffer_size += block_size;
+        length -= block_size;
+
+    }
+
+    return 1;
+}
+
+int guac_webp_write(guac_socket* socket, guac_stream* stream,
+        cairo_surface_t* surface, int quality) {
+
+    guac_webp_stream_writer writer;
+    WebPPicture picture;
+    uint32_t* argb_output;
+
+    int x, y;
+
+    int width = cairo_image_surface_get_width(surface);
+    int height = cairo_image_surface_get_height(surface);
+    int stride = cairo_image_surface_get_stride(surface);
+    cairo_format_t format = cairo_image_surface_get_format(surface);
+    unsigned char* data = cairo_image_surface_get_data(surface);
+
+    if (format != CAIRO_FORMAT_RGB24 && format != CAIRO_FORMAT_ARGB32) {
+        guac_error = GUAC_STATUS_INTERNAL_ERROR;
+        guac_error_message = "Invalid Cairo image format. Unable to create WebP.";
+        return -1;
+    }
+
+    /* Flush pending operations to surface */
+    cairo_surface_flush(surface);
+
+    /* Configure WebP compression bits */
+    WebPConfig config;
+    if (!WebPConfigPreset(&config, WEBP_HINT_DEFAULT, quality))
+        return -1;
+
+    /* Add additional tuning */
+    config.lossless = 0;
+    config.quality = quality;
+    config.thread_level = 1; /* Multi threaded */
+    config.method = 2; /* Compression method (0=fast/larger, 6=slow/smaller) */
+
+    /* Validate configuration */
+    WebPValidateConfig(&config);
+
+    /* Set up WebP picture */
+    WebPPictureInit(&picture);
+    picture.use_argb = 1;
+    picture.width = width;
+    picture.height = height;
+
+    /* Allocate and init writer */
+    WebPPictureAlloc(&picture);
+    picture.writer = guac_webp_stream_write;
+    picture.custom_ptr = &writer;
+    guac_webp_stream_writer_init(&writer, socket, stream);
+
+    /* Copy image data into WebP picture */
+    argb_output = picture.argb;
+    for (y = 0; y < height; y++) {
+
+        /* Get pixels at start of each row */
+        uint32_t* src = (uint32_t*) data;
+        uint32_t* dst = argb_output;
+
+        /* For each pixel in row */
+        for (x = 0; x < width; x++) {
+
+            /* Pull pixel data, removing alpha channel if necessary */
+            uint32_t src_pixel = *src;
+            if (format != CAIRO_FORMAT_ARGB32)
+                src_pixel |= 0xFF000000;
+
+            /* Store converted pixel data */
+            *dst = src_pixel;
+
+            /* Next pixel */
+            src++;
+            dst++;
+
+        }
+
+        /* Next row */
+        data += stride;
+        argb_output += picture.argb_stride;
+
+    }
+
+    /* Encode image */
+    WebPEncode(&config, &picture);
+
+    /* Free picture */
+    WebPPictureFree(&picture);
+
+    /* Ensure all data is written */
+    guac_webp_flush_data(&writer);
+
+    return 0;
+
+}
+

src/libguac/encode-webp.h

@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2015 Glyptodon LLC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef GUAC_ENCODE_WEBP_H
+#define GUAC_ENCODE_WEBP_H
+
+#include "config.h"
+
+#include "socket.h"
+#include "stream.h"
+
+#include <cairo/cairo.h>
+
+/**
+ * Encodes the given surface as a WebP, and sends the resulting data over the
+ * given stream and socket as blobs.
+ *
+ * @param socket
+ *     The socket to send WebP blobs over.
+ *
+ * @param stream
+ *     The stream to associate with each blob.
+ *
+ * @param surface
+ *     The Cairo surface to write to the given stream and socket as PNG blobs.
+ *
+ * @param quality
+ *     The WebP image quality to use.
+ *
+ * @return
+ *     Zero if the encoding operation is successful, non-zero otherwise.
+ */
+int guac_webp_write(guac_socket* socket, guac_stream* stream,
+        cairo_surface_t* surface, int quality);
+
+#endif

src/libguac/guacamole/client.h

@@ -696,11 +696,67 @@ void guac_client_stream_png(guac_client* client, guac_socket* socket,
  *
  * @param surface
  *     A Cairo surface containing the image data to be streamed.
+ *
+ * @param quality
+ *     The JPEG image quality, which must be an integer value between 0 and
+ *     100 inclusive.
  */
 void guac_client_stream_jpeg(guac_client* client, guac_socket* socket,
         guac_composite_mode mode, const guac_layer* layer, int x, int y,
         cairo_surface_t* surface, int quality);
 
+/**
+ * Streams the image data of the given surface over an image stream ("img"
+ * instruction) as WebP-encoded data at the given quality. The image stream
+ * will be automatically allocated and freed. If the server does not support
+ * WebP, this function has no effect, so be sure to check the result of
+ * guac_client_supports_webp() prior to calling this function.
+ *
+ * @param client
+ *     The Guacamole client from which the image stream should be allocated.
+ *
+ * @param socket
+ *     The socket over which instructions associated with the image stream
+ *     should be sent.
+ *
+ * @param mode
+ *     The composite mode to use when rendering the image over the given layer.
+ *
+ * @param layer
+ *     The destination layer.
+ *
+ * @param x
+ *     The X coordinate of the upper-left corner of the destination rectangle
+ *     within the given layer.
+ *
+ * @param y
+ *     The Y coordinate of the upper-left corner of the destination rectangle
+ *     within the given layer.
+ *
+ * @param surface
+ *     A Cairo surface containing the image data to be streamed.
+ *
+ * @param quality
+ *     The WebP image quality, which must be an integer value between 0 and
+ *     100 inclusive.
+ */
+void guac_client_stream_webp(guac_client* client, guac_socket* socket,
+        guac_composite_mode mode, const guac_layer* layer, int x, int y,
+        cairo_surface_t* surface, int quality);
+
+/**
+ * Returns whether the given client supports WebP. If the client does not
+ * support WebP, or the server cannot encode WebP images, zero is returned.
+ *
+ * @param client
+ *     The Guacamole client to check for WebP support.
+ *
+ * @return
+ *     Non-zero if the given client claims to support WebP and the server has
+ *     been built with WebP support, zero otherwise.
+ */
+int guac_client_supports_webp(guac_client* client);
+
 /**
  * The default Guacamole client layer, layer 0.
  */