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问用图像填充Qt-圈
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Stack Overflow用户

提问于 2015-06-22 12:52:37

回答 2查看 2.5K关注 0票数 3

我试着用四张图片填充圆圈。首先，每个照片刷在相同的大小，今后比例尺最终图像与该大小。但结果不是我想要的。

此刻，前景中的圆圈和背景上的照片，如下所示：

如何填充圆圈的照片和删除矩形？

这是我的代码：

QPixmap *CGlobalZone::profPicFromFourPics(QList<QPixmap> pixmapList)
{
        QPixmap *avatar = NULL;
        QImage roundedImage(CGlobalZone::AVATAR_WIDTH_M*2, CGlobalZone::AVATAR_HEIGHT_M*2, QImage::Format_ARGB32);
        roundedImage.fill(Qt::transparent);
        QBrush brush0(pixmapList[0]);
        QBrush brush1(pixmapList[1]);
        QBrush brush2(pixmapList[2]);
        QBrush brush3(pixmapList[3]);
        QPainter painter(&roundedImage);
        QPen pen(QColor(176, 216, 242), 1);
        painter.setRenderHint(QPainter::Antialiasing);
        painter.setBrush(brush0);
        painter.drawRect(0 , 0 , CGlobalZone::AVATAR_WIDTH_M  , CGlobalZone::AVATAR_HEIGHT_M  );
        painter.setBrush(brush1);
        painter.drawRect(CGlobalZone::AVATAR_WIDTH_M , 0 , CGlobalZone::AVATAR_WIDTH_M*2  , CGlobalZone::AVATAR_HEIGHT_M  );
        painter.setBrush(brush2);
        painter.drawRect(CGlobalZone::AVATAR_WIDTH_M , CGlobalZone::AVATAR_HEIGHT_M , CGlobalZone::AVATAR_WIDTH_M*2  , CGlobalZone::AVATAR_HEIGHT_M*2  );
        painter.setBrush(brush3);
        painter.drawRect(0 , CGlobalZone::AVATAR_HEIGHT_M , CGlobalZone::AVATAR_WIDTH_M*2  , CGlobalZone::AVATAR_HEIGHT_M*2  );
        painter.drawEllipse(0, 0, CGlobalZone::AVATAR_WIDTH_M*2-3 , CGlobalZone::AVATAR_HEIGHT_M*2-3 );
        avatar  = new QPixmap(QPixmap::fromImage(roundedImage).scaled(QSize(CGlobalZone::AVATAR_WIDTH_M, CGlobalZone::AVATAR_HEIGHT_M),
                                                    Qt::KeepAspectRatioByExpanding, Qt::SmoothTransformation));
       return avatar;
}

c++

qpainter

回答 2

Stack Overflow用户

回答已采纳

发布于 2015-06-22 13:52:19

我这样做的方式如下(详见源评论)：

// The avatar image. Should be four, but use one for demonstration.
QPixmap source("avatar.png");

// Initialize the avatar and bring it to a standard size.
// This step may be skipped if avatars have the same sizes.
const int width = CGlobalZone::AVATAR_WIDTH_M;
const int height = CGlobalZone::AVATAR_HEIGHT_M;
source = source.scaled(width, height);

// Set up the final image that contains four avatar images.
QPixmap target(2 * width, 2 * height);
target.fill(Qt::transparent);

QPainter painter(&target);

// Set clipped region (circle) in the center of the target image
QRegion r(QRect(width / 2, height / 2, width, height), QRegion::Ellipse);
painter.setClipRegion(r);

painter.drawPixmap(0, 0, source);          // First avatar
painter.drawPixmap(width, 0, source);      // Second avatar
painter.drawPixmap(0, height, source);     // Third avatar
painter.drawPixmap(width, height, source); // Fourth avatar

target.save("test.png");

票数 2

Stack Overflow用户

发布于 2015-06-22 13:36:01

对任务使用画家路径。而不是drawEllipse，你应该做

int dim = CGlobalZone::AVATAR_WIDTH_M*2;
QPainterPath entirePath;
QPainterPath ellipsePath;

entirePath.addRect(0, 0, dim, dim);
ellipsePath.addEllipse(0, 0, dim-3, dim-3);
QPainterPath outOfEllipse = entirePath.subtracted(ellipsePath);
painter.fillPath(outOfEllipse, QBrush(Qt::transparent));

编辑：，因为QPainterPath用于复杂的情况，所以您应该使用QRegion。经过测试，我发现在填充相同路径的内部和外部时，可能会出现小的像素错误(在您的例子中，会很好)。

票数 0

页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持

原文链接：

https://stackoverflow.com/questions/30980484

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