Total makeover of SVG image reader

Improved/fixed canRead(). Added svgz support. Implemented ClipRect,
ScaledClipRect and BackgroundColor support. Avoid data copy when reading
from memory. Improved support reading from sequential devices. Added svg
and svgz files to the qimagereader autotests.

Task-number: QTBUG-8227 and QTBUG-9053
Reviewed-by: Kim

1 files changed, 102 insertions, 55 deletions

diff --git a/src/plugins/imageformats/svg/qsvgiohandler.cpp b/src/plugins/imageformats/svg/qsvgiohandler.cpp
index f3670c6ebc..81555692b8 100644
--- a/src/plugins/imageformats/svg/qsvgiohandler.cpp
+++ b/src/plugins/imageformats/svg/qsvgiohandler.cpp
@@ -48,6 +48,7 @@
 #include "qpixmap.h"
 #include "qpainter.h"
 #include "qvariant.h"
+#include "qbuffer.h"
 #include "qdebug.h"
 
 QT_BEGIN_NAMESPACE
@@ -55,67 +56,54 @@ QT_BEGIN_NAMESPACE
 class QSvgIOHandlerPrivate
 {
 public:
-    QSvgIOHandlerPrivate()
-        : r(new QSvgRenderer()), loaded(false)
+    QSvgIOHandlerPrivate(QSvgIOHandler *qq)
+        : q(qq), loaded(false), readDone(false), backColor(Qt::transparent)
     {}
-    ~QSvgIOHandlerPrivate()
-    {
-        delete r;
-    }
 
     bool load(QIODevice *device);
-    static bool findSvgTag(QIODevice *device);
 
-    QSvgRenderer *r;
-    QSize         defaultSize;
-    QSize         currentSize;
-    bool          loaded;
+    QSvgIOHandler   *q;
+    QSvgRenderer     r;
+    QXmlStreamReader xmlReader;
+    QSize            defaultSize;
+    QRect            clipRect;
+    QSize            scaledSize;
+    QRect            scaledClipRect;
+    bool             loaded;
+    bool             readDone;
+    QColor           backColor;
 };
 
+
 bool QSvgIOHandlerPrivate::load(QIODevice *device)
 {
     if (loaded)
         return true;
+    if (q->format().isEmpty())
+        q->canRead();
+
+    bool res = false;
+    QBuffer *buf = qobject_cast<QBuffer *>(device);
+    if (buf) {
+        res = r.load(buf->data());
+    } else if (q->format() == "svgz") {
+        res = r.load(device->readAll());   // ### can't stream svgz
+    } else {
+        xmlReader.setDevice(device);
+        res = r.load(&xmlReader);   //### doesn't leave pos() correctly
+    }
 
-    if (r->load(device->readAll())) {
-        defaultSize = QSize(r->viewBox().width(), r->viewBox().height());
-        if (currentSize.isEmpty())
-            currentSize = defaultSize;
+    if (res) {
+        defaultSize = QSize(r.viewBox().width(), r.viewBox().height());
+        loaded = true;
     }
-    loaded = r->isValid();
 
     return loaded;
 }
 
-bool QSvgIOHandlerPrivate::findSvgTag(QIODevice *device)
-{
-    qint64 pos = device->pos();
-    device->seek(0);
-    char buffer[256];
-    const char svg_tag[] = "<svg";
-
-    while (1) {
-        int size = device->read(buffer, 256);
-        for (int i=0; i<size - 5; ++i) {
-            if (!memcmp(buffer + i, svg_tag, 4)) {
-                if (buffer[i+4] == ' ' || buffer[i+4] == '\t'
-                    || buffer[i+4] == '\n' || buffer[i+4] == '\r')
-                {
-                    device->seek(pos);
-                    return true;
-                }
-            }
-        }
-        if (device->atEnd())
-            break;
-        device->seek(device->pos()-4);
-    }
-    device->seek(pos);
-    return false;
-}
 
 QSvgIOHandler::QSvgIOHandler()
-    : d(new QSvgIOHandlerPrivate())
+    : d(new QSvgIOHandlerPrivate(this))
 {
 
 }
@@ -129,7 +117,20 @@ QSvgIOHandler::~QSvgIOHandler()
 
 bool QSvgIOHandler::canRead() const
 {
-    return QSvgIOHandlerPrivate::findSvgTag(device());
+    if (!device())
+        return false;
+    if (d->loaded && !d->readDone)
+        return true;        // Will happen if we have been asked for the size
+
+    QByteArray buf = device()->peek(8);
+    if (buf.startsWith("\x1f\x8b")) {
+        setFormat("svgz");
+        return true;
+    } else if (buf.contains("<?xml") || buf.contains("<svg")) {
+        setFormat("svg");
+        return true;
+    }
+    return false;
 }
 
 
@@ -141,14 +142,41 @@ QByteArray QSvgIOHandler::name() const
 
 bool QSvgIOHandler::read(QImage *image)
 {
-    if (d->load(device())) {
-        *image = QImage(d->currentSize, QImage::Format_ARGB32_Premultiplied);
-        if (!d->currentSize.isEmpty()) {
-            image->fill(0x00000000);
+    if (!d->readDone && d->load(device())) {
+        bool xform = (d->clipRect.isValid() || d->scaledSize.isValid() || d->scaledClipRect.isValid());
+        QSize finalSize = d->defaultSize;
+        QRectF bounds;
+        if (xform && !d->defaultSize.isEmpty()) {
+            bounds = QRectF(QPointF(0,0), QSizeF(d->defaultSize));
+            QPoint tr1, tr2;
+            QSizeF sc(1, 1);
+            if (d->clipRect.isValid()) {
+                tr1 = -d->clipRect.topLeft();
+                finalSize = d->clipRect.size();
+            }
+            if (d->scaledSize.isValid()) {
+                sc = QSizeF(qreal(d->scaledSize.width()) / finalSize.width(),
+                            qreal(d->scaledSize.height()) / finalSize.height());
+                finalSize = d->scaledSize;
+            }
+            if (d->scaledClipRect.isValid()) {
+                tr2 = -d->scaledClipRect.topLeft();
+                finalSize = d->scaledClipRect.size();
+            }
+            QTransform t;
+            t.translate(tr2.x(), tr2.y());
+            t.scale(sc.width(), sc.height());
+            t.translate(tr1.x(), tr1.y());
+            bounds = t.mapRect(bounds);
+        }
+        *image = QImage(finalSize, QImage::Format_ARGB32_Premultiplied);
+        if (!finalSize.isEmpty()) {
+            image->fill(d->backColor.rgba());
             QPainter p(image);
-            d->r->render(&p);
+            d->r.render(&p, bounds);
             p.end();
         }
+        d->readDone = true;
         return true;
     }
 
@@ -166,8 +194,17 @@ QVariant QSvgIOHandler::option(ImageOption option) const
         d->load(device());
         return d->defaultSize;
         break;
+    case ClipRect:
+        return d->clipRect;
+        break;
     case ScaledSize:
-        return d->currentSize;
+        return d->scaledSize;
+        break;
+    case ScaledClipRect:
+        return d->scaledClipRect;
+        break;
+    case BackgroundColor:
+        return d->backColor;
         break;
     default:
         break;
@@ -179,12 +216,17 @@ QVariant QSvgIOHandler::option(ImageOption option) const
 void QSvgIOHandler::setOption(ImageOption option, const QVariant & value)
 {
     switch(option) {
-    case Size:
-        d->defaultSize = value.toSize();
-        d->currentSize = value.toSize();
+    case ClipRect:
+        d->clipRect = value.toRect();
         break;
     case ScaledSize:
-        d->currentSize = value.toSize();
+        d->scaledSize = value.toSize();
+        break;
+    case ScaledClipRect:
+        d->scaledClipRect = value.toRect();
+        break;
+    case BackgroundColor:
+        d->backColor = value.value<QColor>();
         break;
     default:
         break;
@@ -198,7 +240,10 @@ bool QSvgIOHandler::supportsOption(ImageOption option) const
     {
     case ImageFormat:
     case Size:
+    case ClipRect:
     case ScaledSize:
+    case ScaledClipRect:
+    case BackgroundColor:
         return true;
     default:
         break;
@@ -206,9 +251,11 @@ bool QSvgIOHandler::supportsOption(ImageOption option) const
     return false;
 }
 
+
 bool QSvgIOHandler::canRead(QIODevice *device)
 {
-    return QSvgIOHandlerPrivate::findSvgTag(device);
+    QByteArray buf = device->peek(8);
+    return buf.startsWith("\x1f\x8b") || buf.contains("<?xml") || buf.contains("<svg");
 }
 
 QT_END_NAMESPACE