diff options
| -rw-r--r-- | src/plugins/imageformats/jpeg/qjpeghandler.cpp | 233 | ||||
| -rw-r--r-- | src/plugins/imageformats/jpeg/qjpeghandler.h | 2 |
2 files changed, 149 insertions, 86 deletions
diff --git a/src/plugins/imageformats/jpeg/qjpeghandler.cpp b/src/plugins/imageformats/jpeg/qjpeghandler.cpp index 8da6610..7165c38 100644 --- a/src/plugins/imageformats/jpeg/qjpeghandler.cpp +++ b/src/plugins/imageformats/jpeg/qjpeghandler.cpp @@ -90,9 +90,6 @@ public: QImage scale(); -protected: - int scaledWidth(void) const; - private: QImageSmoothScalerPrivate *d; virtual QRgb *scanLine(const int line = 0, const QImage *src = 0); @@ -140,11 +137,6 @@ void QImageSmoothScalerPrivate::setup(const int srcWidth, const int srcHeight, hasAlpha = hasAlphaChannel; } -int QImageSmoothScaler::scaledWidth() const -{ - return d->cols; -} - QImageSmoothScaler::~QImageSmoothScaler() { delete d; @@ -443,20 +435,18 @@ QImage QImageSmoothScaler::scale() class jpegSmoothScaler : public QImageSmoothScaler { public: - jpegSmoothScaler(struct jpeg_decompress_struct *info, int dstWidth, int dstHeight) - : QImageSmoothScaler(info->output_width, info->output_height, dstWidth, dstHeight) + jpegSmoothScaler(struct jpeg_decompress_struct *info, const QSize& dstSize, const QRect& clipRect) + : QImageSmoothScaler(clipRect.width(), clipRect.height(), + dstSize.width(), dstSize.height()) { - cinfo = info; - cols24Bit = scaledWidth() * 3; - - cacheHeight = 1; - imageCache = QImage( info->output_width, cacheHeight, QImage::Format_RGB32 ); + cinfo = info; + clip = clipRect; + imageCache = QImage(info->output_width, 1, QImage::Format_RGB32); } private: - int cols24Bit; + QRect clip; QImage imageCache; - int cacheHeight; struct jpeg_decompress_struct *cinfo; QRgb *scanLine(const int line = 0, const QImage *src = 0) @@ -468,33 +458,42 @@ private: Q_UNUSED(src); uchar* data = imageCache.bits(); + + // Read ahead if we haven't reached the first clipped scanline yet. + while (int(cinfo->output_scanline) < clip.y() && + cinfo->output_scanline < cinfo->output_height) + jpeg_read_scanlines(cinfo, &data, 1); + + // Read the next scanline. We assume that "line" + // will never be >= clip.height(). jpeg_read_scanlines(cinfo, &data, 1); - out = (QRgb*)imageCache.scanLine(0); + if (cinfo->output_scanline == cinfo->output_height) + jpeg_finish_decompress(cinfo); + + out = ((QRgb*)data) + clip.x(); // // The smooth scale algorithm only works on 32-bit images; // convert from (8|24) bits to 32. // if (cinfo->output_components == 1) { - in = (uchar*)out + scaledWidth(); - for (uint i = scaledWidth(); i--; ) { - in--; + in = data + clip.right(); + for (int i = clip.width(); i--; ) { out[i] = qRgb(*in, *in, *in); + in--; } - } else if (cinfo->out_color_space == JCS_CMYK) { - int cols32Bit = scaledWidth() * 4; - in = (uchar*)out + cols32Bit; - for (uint i = scaledWidth(); i--; ) { - in -= 4; - int k = in[3]; - out[i] = qRgb(k * in[0] / 255, k * in[1] / 255, k * in[2] / 255); - //out[i] = qRgb(in[0], in[1], in[2]); - } - } else { - in = (uchar*)out + cols24Bit; - for (uint i = scaledWidth(); i--; ) { - in -= 3; + } else if (cinfo->out_color_space == JCS_CMYK) { + in = data + clip.right() * 4; + for (int i = clip.width(); i--; ) { + int k = in[3]; + out[i] = qRgb(k * in[0] / 255, k * in[1] / 255, k * in[2] / 255); + in -= 4; + } + } else { + in = data + clip.right() * 3; + for (int i = clip.width(); i--; ) { out[i] = qRgb(in[0], in[1], in[2]); + in -= 3; } } @@ -693,7 +692,7 @@ static bool read_jpeg_format(QIODevice *device, QImage::Format &format) } static bool ensureValidImage(QImage *dest, struct jpeg_decompress_struct *info, - bool dummy = false) + const QSize& size) { QImage::Format format; switch (info->output_components) { @@ -708,13 +707,8 @@ static bool ensureValidImage(QImage *dest, struct jpeg_decompress_struct *info, return false; // unsupported format } - const QSize size(info->output_width, info->output_height); if (dest->size() != size || dest->format() != format) { - static uchar dummyImage[1]; - if (dummy) // Create QImage but don't read the pixels - *dest = QImage(dummyImage, size.width(), size.height(), format); - else - *dest = QImage(size, format); + *dest = QImage(size, format); if (format == QImage::Format_Indexed8) { dest->setColorCount(256); @@ -727,12 +721,9 @@ static bool ensureValidImage(QImage *dest, struct jpeg_decompress_struct *info, } static bool read_jpeg_image(QIODevice *device, QImage *outImage, - QSize scaledSize, int inQuality ) + QSize scaledSize, const QRect& clipRect, + int inQuality ) { -#ifdef QT_NO_IMAGE_SMOOTHSCALE - Q_UNUSED( scaledSize ); -#endif - struct jpeg_decompress_struct cinfo; struct my_jpeg_source_mgr *iod_src = new my_jpeg_source_mgr(device); @@ -757,10 +748,17 @@ static bool read_jpeg_image(QIODevice *device, QImage *outImage, if (quality < 0) quality = 75; -#ifndef QT_NO_IMAGE_SMOOTHSCALE + // Determine the scale factor to pass to libjpeg for quick downscaling. if (!scaledSize.isEmpty()) { - cinfo.scale_denom = qMin(cinfo.image_width / scaledSize.width(), - cinfo.image_height / scaledSize.height()); + if (clipRect.isEmpty()) { + cinfo.scale_denom = + qMin(cinfo.image_width / scaledSize.width(), + cinfo.image_height / scaledSize.height()); + } else { + cinfo.scale_denom = + qMin(clipRect.width() / scaledSize.width(), + clipRect.height() / scaledSize.height()); + } if (cinfo.scale_denom < 2) { cinfo.scale_denom = 1; } else if (cinfo.scale_denom < 4) { @@ -771,9 +769,19 @@ static bool read_jpeg_image(QIODevice *device, QImage *outImage, cinfo.scale_denom = 8; } cinfo.scale_num = 1; + if (!clipRect.isEmpty()) { + // Correct the scale factor so that we clip accurately. + // It is recommended that the clip rectangle be aligned + // on an 8-pixel boundary for best performance. + while (cinfo.scale_denom > 1 && + ((clipRect.x() % cinfo.scale_denom) != 0 || + (clipRect.y() % cinfo.scale_denom) != 0 || + (clipRect.width() % cinfo.scale_denom) != 0 || + (clipRect.height() % cinfo.scale_denom) != 0)) { + cinfo.scale_denom /= 2; + } + } } -#endif - // If high quality not required, use fast decompression if( quality < HIGH_QUALITY_THRESHOLD ) { @@ -781,54 +789,102 @@ static bool read_jpeg_image(QIODevice *device, QImage *outImage, cinfo.do_fancy_upsampling = FALSE; } + (void) jpeg_calc_output_dimensions(&cinfo); - (void) jpeg_start_decompress(&cinfo); + // Determine the clip region to extract. + QRect imageRect(0, 0, cinfo.output_width, cinfo.output_height); + QRect clip; + if (clipRect.isEmpty()) { + clip = imageRect; + } else if (cinfo.scale_denom == 1) { + clip = clipRect.intersected(imageRect); + } else { + // The scale factor was corrected above to ensure that + // we don't miss pixels when we scale the clip rectangle. + clip = QRect(clipRect.x() / int(cinfo.scale_denom), + clipRect.y() / int(cinfo.scale_denom), + clipRect.width() / int(cinfo.scale_denom), + clipRect.height() / int(cinfo.scale_denom)); + clip = clip.intersected(imageRect); + } #ifndef QT_NO_IMAGE_SMOOTHSCALE - if (scaledSize.isValid() && scaledSize != QSize(cinfo.output_width, cinfo.output_height) + if (scaledSize.isValid() && scaledSize != clip.size() && quality >= HIGH_QUALITY_THRESHOLD) { - jpegSmoothScaler scaler(&cinfo, scaledSize.width(), scaledSize.height()); + (void) jpeg_start_decompress(&cinfo); + + jpegSmoothScaler scaler(&cinfo, scaledSize, clip); *outImage = scaler.scale(); } else #endif { - if (!ensureValidImage(outImage, &cinfo)) + // Allocate memory for the clipped QImage. + if (!ensureValidImage(outImage, &cinfo, clip.size())) longjmp(jerr.setjmp_buffer, 1); - uchar* data = outImage->bits(); - int bpl = outImage->bytesPerLine(); - while (cinfo.output_scanline < cinfo.output_height) { - uchar *d = data + cinfo.output_scanline * bpl; - (void) jpeg_read_scanlines(&cinfo, - &d, - 1); - } - (void) jpeg_finish_decompress(&cinfo); - - if (cinfo.output_components == 3) { - // Expand 24->32 bpp. - for (uint j=0; j<cinfo.output_height; j++) { - uchar *in = outImage->scanLine(j) + cinfo.output_width * 3; - QRgb *out = (QRgb*)outImage->scanLine(j); - - for (uint i=cinfo.output_width; i--;) { - in-=3; - out[i] = qRgb(in[0], in[1], in[2]); + // Avoid memcpy() overhead if grayscale with no clipping. + bool quickGray = (cinfo.output_components == 1 && + clip == imageRect); + if (!quickGray) { + // Ask the jpeg library to allocate a temporary row. + // The library will automatically delete it for us later. + // The libjpeg docs say we should do this before calling + // jpeg_start_decompress(). We can't use "new" here + // because we are inside the setjmp() block and an error + // in the jpeg input stream would cause a memory leak. + JSAMPARRAY rows = (cinfo.mem->alloc_sarray) + ((j_common_ptr)&cinfo, JPOOL_IMAGE, + cinfo.output_width * cinfo.output_components, 1); + + (void) jpeg_start_decompress(&cinfo); + + while (cinfo.output_scanline < cinfo.output_height) { + int y = int(cinfo.output_scanline) - clip.y(); + if (y >= clip.height()) + break; // We've read the entire clip region, so abort. + + (void) jpeg_read_scanlines(&cinfo, rows, 1); + + if (y < 0) + continue; // Haven't reached the starting line yet. + + if (cinfo.output_components == 3) { + // Expand 24->32 bpp. + uchar *in = rows[0] + clip.x() * 3; + QRgb *out = (QRgb*)outImage->scanLine(y); + for (int i = 0; i < clip.width(); ++i) { + *out++ = qRgb(in[0], in[1], in[2]); + in += 3; + } + } else if (cinfo.out_color_space == JCS_CMYK) { + // Convert CMYK->RGB. + uchar *in = rows[0] + clip.x() * 4; + QRgb *out = (QRgb*)outImage->scanLine(y); + for (int i = 0; i < clip.width(); ++i) { + int k = in[3]; + *out++ = qRgb(k * in[0] / 255, k * in[1] / 255, + k * in[2] / 255); + in += 4; + } + } else if (cinfo.output_components == 1) { + // Grayscale. + memcpy(outImage->scanLine(y), + rows[0] + clip.x(), clip.width()); } } - } else if (cinfo.out_color_space == JCS_CMYK) { - for (uint j = 0; j < cinfo.output_height; ++j) { - uchar *in = outImage->scanLine(j) + cinfo.output_width * 4; - QRgb *out = (QRgb*)outImage->scanLine(j); - - for (uint i = cinfo.output_width; i--; ) { - in-=4; - int k = in[3]; - out[i] = qRgb(k * in[0] / 255, k * in[1] / 255, k * in[2] / 255); - } + } else { + // Load unclipped grayscale data directly into the QImage. + (void) jpeg_start_decompress(&cinfo); + while (cinfo.output_scanline < cinfo.output_height) { + uchar *row = outImage->scanLine(cinfo.output_scanline); + (void) jpeg_read_scanlines(&cinfo, &row, 1); } } + + if (cinfo.output_scanline == cinfo.output_height) + (void) jpeg_finish_decompress(&cinfo); + if (cinfo.density_unit == 1) { outImage->setDotsPerMeterX(int(100. * cinfo.X_density / 2.54)); outImage->setDotsPerMeterY(int(100. * cinfo.Y_density / 2.54)); @@ -837,7 +893,7 @@ static bool read_jpeg_image(QIODevice *device, QImage *outImage, outImage->setDotsPerMeterY(int(100. * cinfo.Y_density)); } - if (scaledSize.isValid() && scaledSize != QSize(cinfo.output_width, cinfo.output_height)) + if (scaledSize.isValid() && scaledSize != clip.size()) *outImage = outImage->scaled(scaledSize, Qt::IgnoreAspectRatio, Qt::FastTransformation); } } @@ -1101,7 +1157,7 @@ bool QJpegHandler::read(QImage *image) { if (!canRead()) return false; - return read_jpeg_image(device(), image, scaledSize, quality); + return read_jpeg_image(device(), image, scaledSize, clipRect, quality); } bool QJpegHandler::write(const QImage &image) @@ -1115,6 +1171,7 @@ bool QJpegHandler::supportsOption(ImageOption option) const #ifndef QT_NO_IMAGE_SMOOTHSCALE || option == ScaledSize #endif + || option == ClipRect || option == Size || option == ImageFormat; } @@ -1127,6 +1184,8 @@ QVariant QJpegHandler::option(ImageOption option) const } else if (option == ScaledSize) { return scaledSize; #endif + } else if (option == ClipRect) { + return clipRect; } else if (option == Size) { if (canRead() && !device()->isSequential()) { qint64 pos = device()->pos(); @@ -1157,6 +1216,8 @@ void QJpegHandler::setOption(ImageOption option, const QVariant &value) else if ( option == ScaledSize ) scaledSize = value.toSize(); #endif + else if ( option == ClipRect ) + clipRect = value.toRect(); } QByteArray QJpegHandler::name() const diff --git a/src/plugins/imageformats/jpeg/qjpeghandler.h b/src/plugins/imageformats/jpeg/qjpeghandler.h index 0a14a88..108b131 100644 --- a/src/plugins/imageformats/jpeg/qjpeghandler.h +++ b/src/plugins/imageformats/jpeg/qjpeghandler.h @@ -44,6 +44,7 @@ #include <QtGui/qimageiohandler.h> #include <QtCore/QSize> +#include <QtCore/QRect> QT_BEGIN_NAMESPACE @@ -67,6 +68,7 @@ public: private: int quality; QSize scaledSize; + QRect clipRect; }; QT_END_NAMESPACE |