Qt源码分析--QImage(8)

1.void setDotsPerMeterX(int);

设置每米有多少个像素

/*!Sets the number of pixels that fit horizontally in a physicalmeter, to \a x.Together with dotsPerMeterY(), this number defines the intendedscale and aspect ratio of the image, and determines the scaleat which QPainter will draw graphics on the image. It does notchange the scale or aspect ratio of the image when it is renderedon other paint devices.\sa dotsPerMeterX(), {QImage#Image Information}{Image Information}
*/
void QImage::setDotsPerMeterX(int x)
{if (!d || !x)return;detach();if (d)d->dpmx = x;
}

2.void setDotsPerMeterY(int);

/*!Sets the number of pixels that fit vertically in a physical meter,to \a y.Together with dotsPerMeterX(), this number defines the intendedscale and aspect ratio of the image, and determines the scaleat which QPainter will draw graphics on the image. It does notchange the scale or aspect ratio of the image when it is renderedon other paint devices.\sa dotsPerMeterY(), {QImage#Image Information}{Image Information}
*/
void QImage::setDotsPerMeterY(int y)
{if (!d || !y)return;detach();if (d)d->dpmy = y;
}

3.void fill(const QColor &color);

/*!\fn void QImage::fill(const QColor &color)\overloadFills the entire image with the given \a color.If the depth of the image is 1, the image will be filled with 1 if\a color equals Qt::color1; it will otherwise be filled with 0.If the depth of the image is 8, the image will be filled with theindex corresponding the \a color in the color table if present; itwill otherwise be filled with 0.\since 4.8
*/
void QImage::fill(const QColor &color)
{if (!d)return;detach();// In case we run out of memoryif (!d)return;QRgba64 opaque = color.rgba64();opaque.setAlpha(65535);switch (d->format) {case QImage::Format_RGB32:case QImage::Format_ARGB32:fill(color.rgba());break;case QImage::Format_ARGB32_Premultiplied:fill(qPremultiply(color.rgba()));break;case QImage::Format_RGBX8888:fill(ARGB2RGBA(color.rgba() | 0xff000000));break;case QImage::Format_RGBA8888:fill(ARGB2RGBA(color.rgba()));break;case QImage::Format_RGBA8888_Premultiplied:fill(ARGB2RGBA(qPremultiply(color.rgba())));break;case QImage::Format_BGR30:fill(qConvertRgb64ToRgb30<PixelOrderBGR>(opaque));break;case QImage::Format_RGB30:fill(qConvertRgb64ToRgb30<PixelOrderRGB>(opaque));break;case QImage::Format_RGB16:fill((uint) qConvertRgb32To16(color.rgba()));break;case QImage::Format_Indexed8: {uint pixel = 0;for (int i=0; i<d->colortable.size(); ++i) {if (color.rgba() == d->colortable.at(i)) {pixel = i;break;}}fill(pixel);break;}case QImage::Format_Mono:case QImage::Format_MonoLSB:if (color == Qt::color1)fill((uint) 1);elsefill((uint) 0);break;case QImage::Format_RGBX64:qt_rectfill<quint64>(reinterpret_cast<quint64*>(d->data), opaque,0, 0, d->width, d->height, d->bytes_per_line);break;case QImage::Format_RGBA64:qt_rectfill<quint64>(reinterpret_cast<quint64*>(d->data), color.rgba64(),0, 0, d->width, d->height, d->bytes_per_line);break;case QImage::Format_RGBA64_Premultiplied:qt_rectfill<quint64>(reinterpret_cast<quint64 *>(d->data), color.rgba64().premultiplied(),0, 0, d->width, d->height, d->bytes_per_line);break;default: {QPainter p(this);p.setCompositionMode(QPainter::CompositionMode_Source);p.fillRect(rect(), color);}}
}/*!\fn void QImage::fill(uint pixelValue)Fills the entire image with the given \a pixelValue.If the depth of this image is 1, only the lowest bit is used. Ifyou say fill(0), fill(2), etc., the image is filled with 0s. Ifyou say fill(1), fill(3), etc., the image is filled with 1s. Ifthe depth is 8, the lowest 8 bits are used and if the depth is 16the lowest 16 bits are used.If the image depth is higher than 32bit the result is undefined.\note There are no corresponding value getter, though QImage::pixelIndex()will return the same value for indexed formats, and QImage::pixel() forRGB32, ARGB32, and ARGB32PM formats.\sa depth(), {QImage#Image Transformations}{Image Transformations}
*/
void QImage::fill(uint pixel)
{if (!d)return;detach();// In case detach() ran out of memoryif (!d)return;if (d->depth == 1 || d->depth == 8) {int w = d->width;if (d->depth == 1) {if (pixel & 1)pixel = 0xffffffff;elsepixel = 0;w = (w + 7) / 8;} else {pixel &= 0xff;}qt_rectfill<quint8>(d->data, pixel, 0, 0,w, d->height, d->bytes_per_line);return;} else if (d->depth == 16) {if (d->format == Format_RGB444)pixel |= 0xf000;qt_rectfill<quint16>(reinterpret_cast<quint16*>(d->data), pixel,0, 0, d->width, d->height, d->bytes_per_line);return;} else if (d->depth == 24) {if (d->format == Format_RGB666)pixel |= 0xfc0000;qt_rectfill<quint24>(reinterpret_cast<quint24*>(d->data), pixel,0, 0, d->width, d->height, d->bytes_per_line);return;} else if (d->depth == 64) {qt_rectfill<quint64>(reinterpret_cast<quint64*>(d->data), QRgba64::fromArgb32(pixel),0, 0, d->width, d->height, d->bytes_per_line);return;}if (d->format == Format_RGB32)pixel |= 0xff000000;if (d->format == Format_RGBX8888)
#if Q_BYTE_ORDER == Q_LITTLE_ENDIANpixel |= 0xff000000;
#elsepixel |= 0x000000ff;
#endifif (d->format == Format_BGR30 || d->format == Format_RGB30)pixel |= 0xc0000000;qt_rectfill<uint>(reinterpret_cast<uint*>(d->data), pixel,0, 0, d->width, d->height, d->bytes_per_line);
}template <class T> static
inline void qt_rectfill(T *dest, T value,int x, int y, int width, int height, qsizetype stride)
{char *d = reinterpret_cast<char*>(dest + x) + y * stride;if (uint(stride) == (width * sizeof(T))) {qt_memfill(reinterpret_cast<T*>(d), value, qsizetype(width) * height);} else {for (int j = 0; j < height; ++j) {dest = reinterpret_cast<T*>(d);qt_memfill(dest, value, width);d += stride;}}
}template<> inline void qt_memfill(quint8 *dest, quint8 color, qsizetype count)
{memset(dest, color, count);
}

先把QColor转成整数，然后调用fill(uint pixel)填充。

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