demos/qtdemo/imageitem.cpp
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     1 /****************************************************************************
       
     2 **
       
     3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
       
     4 ** All rights reserved.
       
     5 ** Contact: Nokia Corporation (qt-info@nokia.com)
       
     6 **
       
     7 ** This file is part of the demonstration applications of the Qt Toolkit.
       
     8 **
       
     9 ** $QT_BEGIN_LICENSE:LGPL$
       
    10 ** No Commercial Usage
       
    11 ** This file contains pre-release code and may not be distributed.
       
    12 ** You may use this file in accordance with the terms and conditions
       
    13 ** contained in the Technology Preview License Agreement accompanying
       
    14 ** this package.
       
    15 **
       
    16 ** GNU Lesser General Public License Usage
       
    17 ** Alternatively, this file may be used under the terms of the GNU Lesser
       
    18 ** General Public License version 2.1 as published by the Free Software
       
    19 ** Foundation and appearing in the file LICENSE.LGPL included in the
       
    20 ** packaging of this file.  Please review the following information to
       
    21 ** ensure the GNU Lesser General Public License version 2.1 requirements
       
    22 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
       
    23 **
       
    24 ** In addition, as a special exception, Nokia gives you certain additional
       
    25 ** rights.  These rights are described in the Nokia Qt LGPL Exception
       
    26 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
       
    27 **
       
    28 ** If you have questions regarding the use of this file, please contact
       
    29 ** Nokia at qt-info@nokia.com.
       
    30 **
       
    31 **
       
    32 **
       
    33 **
       
    34 **
       
    35 **
       
    36 **
       
    37 **
       
    38 ** $QT_END_LICENSE$
       
    39 **
       
    40 ****************************************************************************/
       
    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 }