GUAC-1305: Add support for WebP encoded images. Added optional dependency on libwebp.

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${have_webp}" = "xno"
+    then
+        AC_MSG_WARN([
+  --------------------------------------------
+   Unable to find libwebp.
+   guacd will not support WebP image encoding.
+  --------------------------------------------])
+    else
+        AC_DEFINE([ENABLE_WEBP],, [Whether WebP support is enabled])
+    fi
+fi
+
+AM_CONDITIONAL([ENABLE_WEBP], [test "x${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/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/encode-webp.c

@@ -0,0 +1,243 @@
+/*
+ * 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 <inttypes.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+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
+ *     True if writing was successful, false 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;
+    if (writer == NULL) {
+        return 0;
+    }
+
+    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) {
+
+    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);
+
+    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);
+
+    unsigned char* data = cairo_image_surface_get_data(surface);
+
+    /* Configure WebP compression bits */
+    WebPConfig config;
+    if (!WebPConfigPreset(&config, WEBP_HINT_DEFAULT, quality)) return -1;  // version error
+    /* 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) */
+
+    WebPValidateConfig(&config);  /* verify parameter ranges */
+
+    /* Set up WebP picture and writer */
+    guac_webp_stream_writer writer;
+    WebPPicture picture;
+    WebPPictureInit(&picture);
+    picture.use_argb = 1;
+    picture.width = width;
+    picture.height = height;
+    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 */
+    for (int y = 0; y < height; ++y) {
+
+        unsigned char *inptr = data + (stride * y);
+        unsigned char *outptr = (unsigned char*)&picture.argb[y * picture.argb_stride];
+
+        for (int x = 0; x < width; ++x) {
+
+            outptr[0] = *inptr++; // B
+            outptr[1] = *inptr++; // G
+            outptr[2] = *inptr++; // R
+
+            if (format != CAIRO_FORMAT_ARGB32) {
+                outptr[3] = 0xFF;
+            }
+            else {
+                outptr[3] = *inptr; // A
+            }
+
+            inptr++;
+            outptr += 4;
+
+        }
+    }
+
+    /* 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