demos/qtdemo/imageitem.cpp

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  41
  42 #include "imageitem.h"
  43 #include "colors.h"
  44
  45 ImageItem::ImageItem(const QImage &image, int maxWidth, int maxHeight, QGraphicsScene *scene,
  46         QGraphicsItem *parent, bool adjustSize, float scale) : DemoItem(scene, parent)
  47 {
  48     this->image = image;
  49     this->maxWidth = maxWidth;
  50     this->maxHeight = maxHeight;
  51     this->adjustSize = adjustSize;
  52     this->scale = scale;
  53 }
  54
  55 QImage *ImageItem::createImage(const QMatrix &matrix) const
  56 {
  57     QImage *original = new QImage(image);
  58     if (original->isNull()){
  59         return original; // nothing we can do about it...
  60     }
  61
  62     QPoint size = matrix.map(QPoint(this->maxWidth, this->maxHeight));
  63     float w = size.x(); // x, y is the used as width, height
  64     float h = size.y();
  65
  66     // Optimization: if image is smaller than maximum allowed size, just return the loaded image
  67     if (original->size().height() <= h && original->size().width() <= w && !this->adjustSize && this->scale == 1)
  68         return original;
  69
  70     // Calculate what the size of the final image will be:
  71     w = qMin(w, float(original->size().width()) * this->scale);
  72     h = qMin(h, float(original->size().height()) * this->scale);
  73
  74     float adjustx = 1.0f;
  75     float adjusty = 1.0f;
  76     if (this->adjustSize){
  77         adjustx = qMin(matrix.m11(), matrix.m22());
  78         adjusty = matrix.m22() < adjustx ? adjustx : matrix.m22();
  79         w *= adjustx;
  80         h *= adjusty;
  81     }
  82
  83     // Create a new image with correct size, and draw original on it
  84     QImage *image = new QImage(int(w+2), int(h+2), QImage::Format_ARGB32_Premultiplied);
  85     image->fill(QColor(0, 0, 0, 0).rgba());
  86     QPainter painter(image);
  87     painter.setRenderHints(QPainter::Antialiasing | QPainter::SmoothPixmapTransform);
  88     if (this->adjustSize)
  89         painter.scale(adjustx, adjusty);
  90     if (this->scale != 1)
  91        painter.scale(this->scale, this->scale);
  92     painter.drawImage(0, 0, *original);
  93
  94     if (!this->adjustSize){
  95        // Blur out edges
  96        int blur = 30;
  97        if (h < original->height()){
  98            QLinearGradient brush1(0, h - blur, 0, h);
  99            brush1.setSpread(QGradient::PadSpread);
 100            brush1.setColorAt(0.0, QColor(0, 0, 0, 0));
 101            brush1.setColorAt(1.0, Colors::sceneBg1);
 102            painter.fillRect(0, int(h) - blur, original->width(), int(h), brush1);
 103        }
 104        if (w < original->width()){
 105            QLinearGradient brush2(w - blur, 0, w, 0);
 106            brush2.setSpread(QGradient::PadSpread);
 107            brush2.setColorAt(0.0, QColor(0, 0, 0, 0));
 108            brush2.setColorAt(1.0, Colors::sceneBg1);
 109            painter.fillRect(int(w) - blur, 0, int(w), original->height(), brush2);
 110        }
 111     }
 112     delete original;
 113     return image;
 114 }