Use libjpeg directly

ThinClient.pro

@@ -19,7 +19,7 @@ QML_IMPORT_PATH =
 include(deployment.pri)
 
 
-unix|win32: LIBS += -L$$PWD/../libvnc/libvncclient/.libs/ -lvncclient -lEGL
+unix|win32: LIBS += -L$$PWD/../libvnc/libvncclient/.libs/ -lvncclient -lEGL -ljpeg
 
 INCLUDEPATH += $$PWD/../libvnc
 DEPENDPATH += $$PWD/../libvnc

ThinClient.pro.user

 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE QtCreatorProject>
-<!-- Written by QtCreator 3.5.1, 2016-07-19T13:32:08. -->
+<!-- Written by QtCreator 3.5.1, 2016-07-20T14:21:50. -->
 <qtcreator>
  <data>
   <variable>EnvironmentId</variable>

dispatcher.cpp

@@ -37,8 +37,7 @@ void Dispatcher::GotBitmap(rfbClient *client, const uint8_t *buffer, int x, int
 rfbBool Dispatcher::GotJpeg(rfbClient *client, const uint8_t *buffer, int length, int x, int y, int w, int h)
 {
     Dispatcher *dispatcher = static_cast<Dispatcher *>(rfbClientGetClientData(client, 0));
-    Jpeg *jpeg = new Jpeg(QByteArray::fromRawData((const char *) buffer, length),
-                          dispatcher->uploader()->gotJpeg(x, y, w, h));
+    Jpeg *jpeg = new Jpeg((unsigned char*)buffer, length, dispatcher->uploader()->gotJpeg(x, y, w, h));
     dispatcher->queue()->enqueue(jpeg);
     return TRUE;
 }

draw_shader.fsh

@@ -4,5 +4,5 @@ varying highp vec3 varcolor;
 
 void main(void)
 {
-    gl_FragColor = vec4(texture2D(texture, vartexcoord).bgr + varcolor, 1.0);
+    gl_FragColor = vec4(texture2D(texture, vartexcoord).rgb + varcolor, 1.0);
 }

jpegdecoder.cpp

 #include "jpegdecoder.h"
 
+
+
 JpegDecoder::JpegDecoder(ConcurrentQueue<Jpeg *, 64u> *queue, QObject *parent) :
     QObject(parent), m_queue(queue)
 {
@@ -10,9 +12,36 @@ void JpegDecoder::operate()
     Jpeg *jpeg;
     forever {
         jpeg = m_queue->dequeue();
-        QImage image;
-        image.loadFromData(jpeg->data, "JPEG");
-        emit finished(image, image.width(), image.height(), jpeg->index);
+
+        struct jpeg_decompress_struct cinfo;
+        struct error_mgr jerr;
+        cinfo.err = jpeg_std_error(&jerr.mgr);
+        jerr.mgr.error_exit = error_exit;
+        if (setjmp(jerr.setjmp_buffer)) {
+            jpeg_destroy_decompress(&cinfo);
+            return;
+        }
+        jpeg_create_decompress(&cinfo);
+        cinfo.do_fancy_upsampling = TRUE;
+        cinfo.dct_method = JDCT_IFAST;
+
+        jpeg_mem_src(&cinfo, jpeg->data, jpeg->length);
+        (void) jpeg_read_header(&cinfo, TRUE);
+        (void) jpeg_start_decompress(&cinfo);
+
+        JSAMPLE *samples = new JSAMPLE[cinfo.output_width * cinfo.output_height * cinfo.output_components];
+        JSAMPROW *rows = new JSAMPROW[cinfo.output_height * cinfo.output_components];
+        for(size_t i = 0; i < cinfo.output_height; i++) {
+            rows[i] = samples + (i * cinfo.output_width * cinfo.output_components);
+        }
+
+        while (cinfo.output_scanline < cinfo.output_height) {
+            jpeg_read_scanlines(&cinfo, rows + cinfo.output_scanline, 1);
+        }
+        (void) jpeg_finish_decompress(&cinfo);
+        emit finished(samples, cinfo.output_width, cinfo.output_height, jpeg->index);
         delete jpeg;
+        delete rows;
+        jpeg_destroy_decompress(&cinfo);
     }
 }

jpegdecoder.h

@@ -2,28 +2,29 @@
 #define JPEGDECODER_H
 
 #include <QObject>
-#include <QByteArray>
-#include <QPoint>
-#include <QSize>
-#include <QImage>
 #include <QDebug>
 
+// jpeglib requires stdlib.h
+#include <stdio.h>
+#include <jpeglib.h>
+// setjmp.h is required for error handling
+#include <setjmp.h>
+
 #include "concurrentqueue.h"
 
-struct Jpeg {
-    Jpeg(const QByteArray &d, const int i) :
-        data(d), index(i)
+struct Jpeg
+{
+    Jpeg(uint8_t *d, const int l, const int i) :
+        data(d), length(l), index(i)
     {
     }
     ~Jpeg()
     {
-        // QByteArray::fromRawData: " QByteArray does not take ownership of data,
-        // so the QByteArray destructor will never delete the raw data,
-        // even when the last QByteArray referring to data is destroyed."
-        delete[] data.constData();
+        delete[] data;
     }
 
-    QByteArray data;
+    uint8_t *data;
+    int length;
     int index;
 };
 
@@ -39,9 +40,25 @@ public:
     JpegDecoder(ConcurrentQueue<Jpeg*, 64u> *queue, QObject *parent = 0);
     ConcurrentQueue<Jpeg*, 64u> *m_queue;
 signals:
-    void finished(const QImage &image, const int width, const int height, const int index);
+    void finished(const unsigned char *image, const int width, const int height, const int index);
 public slots:
     void operate();
 };
 
+struct error_mgr
+{
+    struct jpeg_error_mgr mgr;
+    jmp_buf setjmp_buffer;
+};
+
+typedef struct error_mgr* error_ptr;
+
+METHODDEF(void)
+error_exit (j_common_ptr cinfo)
+{
+  error_ptr myerr = (error_ptr) cinfo->err;
+  (*cinfo->err->output_message) (cinfo);
+  longjmp(myerr->setjmp_buffer, 1);
+}
+
 #endif // JPEGDECODER_H

qvnc.h

 #ifndef VNC_H
 #define VNC_H
 
-#define DECODER_COUNT 2
+#define DECODER_COUNT 64
 
 #include <QQuickWindow>
 #include <QObject>

uploader.cpp

@@ -223,7 +223,7 @@ int Uploader::gotJpeg(const quint32 x, const quint32 y, const quint32 width, con
     GLuint id;
     m_functions->glGenTextures(1, &id);
     m_functions->glBindTexture(GL_TEXTURE_2D, id);
-    m_functions->glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, real_width, real_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
+    m_functions->glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, real_width, real_height, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
     m_textures->append(id);
 
     float bottom = (float) height / (float) real_height;
@@ -273,12 +273,13 @@ int Uploader::gotJpeg(const quint32 x, const quint32 y, const quint32 width, con
     return m_textures->size() - 1;
 }
 
-void Uploader::finishedJpeg(const QImage &image, const quint32 width, const quint32 height, const int index)
+void Uploader::finishedJpeg(const unsigned char *image, const quint32 width, const quint32 height, const int index)
 {
     m_jpegs--;
     m_functions->glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
     m_functions->glBindTexture(GL_TEXTURE_2D, m_textures->at(index));
-    m_functions->glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, image.constBits());
+    m_functions->glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, GL_RGB, GL_UNSIGNED_BYTE, image);
+    delete[] image;
     if(m_jpegs == 0 && m_finished) {
         m_functions->glBindTexture(GL_TEXTURE_2D, 0);
         m_functions->glFinish();

uploader.h

@@ -69,7 +69,7 @@ public slots:
     void createContext(QOpenGLContext *context);
     void cleanup();
 
-    void finishedJpeg(const QImage &image, const quint32 width, const quint32 height, int index);
+    void finishedJpeg(const unsigned char *image, const quint32 width, const quint32 height, int index);
 };
 
 #endif // UPLOADER_H