QPngHandlerPrivate Class Reference

Public Types
enum	State { Ready, ReadHeader, ReadingEnd, Error }

Public Functions
	QPngHandlerPrivate (QPngHandler *qq)
QImage::Format	readImageFormat ()
bool	readPngHeader ()
bool	readPngImage (QImage *image)
void	readPngTexts (png_info *info)

Public Variables
QString	description
png_info *	end_info
float	gamma
png_info *	info_ptr
png_struct *	png_ptr
QPngHandler *	q
int	quality
QStringList	readTexts
png_byte **	row_pointers
State	state

Detailed Description

Definition at line 108 of file qpnghandler.cpp.

Enumerations

State

enum QPngHandlerPrivate::State

Enumerator
Ready
ReadHeader
ReadingEnd
Error

Definition at line 111 of file qpnghandler.cpp.

               {
        Ready,
        ReadHeader,
        ReadingEnd,
        Error
    };

Constructors and Destructors

QPngHandlerPrivate()

QPngHandlerPrivate::QPngHandlerPrivate ( QPngHandler *  qq )

inline

Definition at line 118 of file qpnghandler.cpp.

        : gamma(0.0), quality(2), png_ptr(0), info_ptr(0),
          end_info(0), row_pointers(0), state(Ready), q(qq)
    { }

Functions

readImageFormat()

QImage::Format QPngHandlerPrivate::readImageFormat

(

)

Definition at line 569 of file qpnghandler.cpp.

Referenced by QPngHandler::option().

{
        QImage::Format format = QImage::Format_Invalid;
        png_uint_32 width, height;
        int bit_depth, color_type;
        png_colorp palette;
        int num_palette;
        png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, 0, 0, 0);
        if (color_type == PNG_COLOR_TYPE_GRAY) {
            // Black & White or 8-bit grayscale
            if (bit_depth == 1 && png_get_channels(png_ptr, info_ptr) == 1) {
                format = QImage::Format_Mono;
            } else if (bit_depth == 16 && png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
                format = QImage::Format_ARGB32;
            } else {
                format = QImage::Format_Indexed8;
            }
        } else if (color_type == PNG_COLOR_TYPE_PALETTE
                   && png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette)
                   && num_palette <= 256)
        {
            // 1-bit and 8-bit color
            if (bit_depth != 1)
                png_set_packing(png_ptr);
            png_read_update_info(png_ptr, info_ptr);
            png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, 0, 0, 0);
            format = bit_depth == 1 ? QImage::Format_Mono : QImage::Format_Indexed8;
        } else {
            // 32-bit
            if (bit_depth == 16)
                png_set_strip_16(png_ptr);

            format = QImage::Format_ARGB32;
            // Only add filler if no alpha, or we can get 5 channel data.
            if (!(color_type & PNG_COLOR_MASK_ALPHA)
                && !png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
                // We want 4 bytes, but it isn't an alpha channel
                format = QImage::Format_RGB32;
            }
        }

        return format;
}

readPngHeader()

bool Q_INTERNAL_WIN_NO_THROW QPngHandlerPrivate::readPngHeader

(

)

Warning

This function is not part of the public interface.

Definition at line 423 of file qpnghandler.cpp.

Referenced by QPngHandler::option(), and readPngImage().

{
    state = Error;
    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,0,0,0);
    if (!png_ptr)
        return false;

    png_set_error_fn(png_ptr, 0, 0, qt_png_warning);

    info_ptr = png_create_info_struct(png_ptr);
    if (!info_ptr) {
        png_destroy_read_struct(&png_ptr, 0, 0);
        png_ptr = 0;
        return false;
    }

    end_info = png_create_info_struct(png_ptr);
    if (!end_info) {
        png_destroy_read_struct(&png_ptr, &info_ptr, 0);
        png_ptr = 0;
        return false;
    }

    if (setjmp(png_jmpbuf(png_ptr))) {
        png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
        png_ptr = 0;
        return false;
    }

    png_set_read_fn(png_ptr, this, iod_read_fn);
    png_read_info(png_ptr, info_ptr);

    readPngTexts(info_ptr);

    state = ReadHeader;
    return true;
}

readPngImage()

bool Q_INTERNAL_WIN_NO_THROW QPngHandlerPrivate::readPngImage

(

QImage *

outImage

)

Warning

This function is not part of the public interface.

Definition at line 464 of file qpnghandler.cpp.

Referenced by QPngHandler::read().

{
    if (state == Error)
        return false;

    if (state == Ready && !readPngHeader()) {
        state = Error;
        return false;
    }

    row_pointers = 0;
    if (setjmp(png_jmpbuf(png_ptr))) {
        png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
        delete [] row_pointers;
        png_ptr = 0;
        state = Error;
        return false;
    }

    setup_qt(*outImage, png_ptr, info_ptr, gamma);

    if (outImage->isNull()) {
        png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
        delete [] row_pointers;
        png_ptr = 0;
        state = Error;
        return false;
    }

    png_uint_32 width = 0;
    png_uint_32 height = 0;
    png_int_32 offset_x = 0;
    png_int_32 offset_y = 0;
    int bit_depth = 0;
    int color_type = 0;
    int unit_type = PNG_OFFSET_PIXEL;
    png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
                 0, 0, 0);
    png_get_oFFs(png_ptr, info_ptr, &offset_x, &offset_y, &unit_type);

    uchar *data = outImage->bits();
    int bpl = outImage->bytesPerLine();
    row_pointers = new png_bytep[height];

    for (uint y = 0; y < height; y++)
        row_pointers[y] = data + y * bpl;

    png_read_image(png_ptr, row_pointers);

#if 0 // libpng takes care of this.
    png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)
        if (outImage->depth()==32 && png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
            QRgb trans = 0xFF000000 | qRgb(
                (info_ptr->trans_values.red << 8 >> bit_depth)&0xff,
                (info_ptr->trans_values.green << 8 >> bit_depth)&0xff,
                (info_ptr->trans_values.blue << 8 >> bit_depth)&0xff);
            for (uint y=0; y<height; y++) {
                for (uint x=0; x<info_ptr->width; x++) {
                    if (((uint**)jt)[y][x] == trans) {
                        ((uint**)jt)[y][x] &= 0x00FFFFFF;
                    } else {
                    }
                }
            }
        }
#endif

    outImage->setDotsPerMeterX(png_get_x_pixels_per_meter(png_ptr,info_ptr));
    outImage->setDotsPerMeterY(png_get_y_pixels_per_meter(png_ptr,info_ptr));

    if (unit_type == PNG_OFFSET_PIXEL)
        outImage->setOffset(QPoint(offset_x, offset_y));

    state = ReadingEnd;
    png_read_end(png_ptr, end_info);

#ifndef QT_NO_IMAGE_TEXT
    readPngTexts(end_info);
    for (int i = 0; i < readTexts.size()-1; i+=2)
        outImage->setText(readTexts.at(i), readTexts.at(i+1));
#endif

    png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
    delete [] row_pointers;
    png_ptr = 0;
    state = Ready;

    // sanity check palette entries
    if (color_type == PNG_COLOR_TYPE_PALETTE
        && outImage->format() == QImage::Format_Indexed8) {
        int color_table_size = outImage->colorCount();
        for (int y=0; y<(int)height; ++y) {
            uchar *p = FAST_SCAN_LINE(data, bpl, y);
            uchar *end = p + width;
            while (p < end) {
                if (*p >= color_table_size)
                    *p = 0;
                ++p;
            }
        }
    }

    return true;
}

readPngTexts()

void Q_INTERNAL_WIN_NO_THROW QPngHandlerPrivate::readPngTexts

(

png_info *

info

)

Warning

This function is not part of the public interface.

Definition at line 391 of file qpnghandler.cpp.

Referenced by readPngHeader(), and readPngImage().

{
#ifndef QT_NO_IMAGE_TEXT
    png_textp text_ptr;
    int num_text=0;
    png_get_text(png_ptr, info, &text_ptr, &num_text);

    while (num_text--) {
        QString key, value;
        key = QString::fromLatin1(text_ptr->key);
#if defined(PNG_iTXt_SUPPORTED)
        if (text_ptr->itxt_length) {
            value = QString::fromUtf8(text_ptr->text, int(text_ptr->itxt_length));
        } else
#endif
        {
            value = QString::fromLatin1(text_ptr->text, int(text_ptr->text_length));
        }
        if (!description.isEmpty())
            description += QLatin1String("\n\n");
        description += key + QLatin1String(": ") + value.simplified();
        readTexts.append(key);
        readTexts.append(value);
        text_ptr++;
    }
#endif
}

Properties

description

QString QPngHandlerPrivate::description

Definition at line 125 of file qpnghandler.cpp.

Referenced by QPngHandler::option(), readPngTexts(), QPngHandler::setOption(), and QPngHandler::write().

end_info

png_info* QPngHandlerPrivate::end_info

Definition at line 130 of file qpnghandler.cpp.

Referenced by readPngHeader(), readPngImage(), and QPngHandler::~QPngHandler().

gamma

float QPngHandlerPrivate::gamma

Definition at line 123 of file qpnghandler.cpp.

Referenced by QPngHandler::option(), readPngImage(), QPngHandler::setOption(), and QPngHandler::write().

info_ptr

png_info* QPngHandlerPrivate::info_ptr

Definition at line 129 of file qpnghandler.cpp.

Referenced by QPngHandler::option(), readImageFormat(), readPngHeader(), readPngImage(), and QPngHandler::~QPngHandler().

png_ptr

png_struct* QPngHandlerPrivate::png_ptr

Definition at line 128 of file qpnghandler.cpp.

Referenced by QPngHandler::option(), readImageFormat(), readPngHeader(), readPngImage(), readPngTexts(), and QPngHandler::~QPngHandler().

q

QPngHandler* QPngHandlerPrivate::q

Definition at line 141 of file qpnghandler.cpp.

Referenced by iod_read_fn().

quality

int QPngHandlerPrivate::quality

Definition at line 124 of file qpnghandler.cpp.

Referenced by QPngHandler::option(), QPngHandler::setOption(), and QPngHandler::write().

readTexts

QStringList QPngHandlerPrivate::readTexts

Definition at line 126 of file qpnghandler.cpp.

Referenced by readPngImage(), and readPngTexts().

row_pointers

png_byte** QPngHandlerPrivate::row_pointers

Definition at line 131 of file qpnghandler.cpp.

Referenced by readPngImage().

state

State QPngHandlerPrivate::state

Definition at line 139 of file qpnghandler.cpp.

Referenced by QPngHandler::canRead(), iod_read_fn(), QPngHandler::option(), readPngHeader(), and readPngImage().

---

The documentation for this class was generated from the following file:

• /src/gui/image/qpnghandler.cpp