class ImageViewer

** ** Copyright (C) 2004-2005 Trolltech AS. All rights reserved. ** ** This file is part of the example classes of the Qt Toolkit. ** ** This file may be used under the terms of the GNU General Public ** License version 2.0 as published by the Free Software Foundation ** and appearing in the file LICENSE.GPL included in the packaging of ** this file. Please review the following information to ensure GNU ** General Public Licensing requirements will be met: ** www.trolltech.com/products/qt/opensource.html ** ** If you are unsure which license is appropriate for your use, please ** review the following information: ** www.trolltech.com/products/qt/licensing.html or contact the ** sales department at sales@trolltech.com. ** ** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE ** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. **

** Translated to QtRuby by Richard Dale

Public Class Methods

new(parent = nil) click to toggle source

Calls superclass method

# File examples/widgets/imageviewer/imageviewer.rb, line 37
def initialize(parent = nil)
        super(parent)
        @imageLabel = Qt::Label.new
        @imageLabel.backgroundRole = Qt::Palette::Base
        @imageLabel.setSizePolicy(Qt::SizePolicy::Ignored, Qt::SizePolicy::Ignored)
        @imageLabel.scaledContents = true

        @scrollArea = Qt::ScrollArea.new
        @scrollArea.backgroundRole = Qt::Palette::Dark
        @scrollArea.widget = @imageLabel
        setCentralWidget(@scrollArea)

        createActions()
        createMenus()

        setWindowTitle(tr("Image Viewer"))
        resize(500, 400)
        @printer = Qt::Printer.new
end

Public Instance Methods

about() click to toggle source

# File examples/widgets/imageviewer/imageviewer.rb, line 117
def about()
        Qt::MessageBox::about(self, tr("About Image Viewer"),
                        tr("<p>The <b>Image Viewer</b> example shows how to combine Qt::Label " +
                        "and Qt::ScrollArea to display an image. Qt::Label is typically used " +
                        "for displaying a text, but it can also display an image. " +
                        "Qt::ScrollArea provides a scrolling view around another widget. " +
                        "If the child widget exceeds the size of the frame, Qt::ScrollArea " +
                        "automatically provides scroll bars. </p><p>The example " +
                        "demonstrates how Qt::Label's ability to scale its contents " +
                        "(Qt::Label::scaledContents), and Qt::ScrollArea's ability to " +
                        "automatically resize its contents " +
                        "(Qt::ScrollArea.widgetResizable), can be used to implement " +
                        "zooming and scaling features. </p><p>In addition the example " +
                        "shows how to use Qt::Painter to print an image.</p>"))
end

adjustScrollBar(scrollBar, factor) click to toggle source

# File examples/widgets/imageviewer/imageviewer.rb, line 215
def adjustScrollBar(scrollBar, factor)
        scrollBar.value = factor * scrollBar.value
                                                        + ((factor - 1) * scrollBar.pageStep/2)
end

createActions() click to toggle source

# File examples/widgets/imageviewer/imageviewer.rb, line 133
def createActions()
        @openAct = Qt::Action.new(tr("&Open..."), self)
        @openAct.shortcut = Qt::KeySequence.new(tr("Ctrl+O"))
        connect(@openAct, SIGNAL('triggered()'), self, SLOT('open()'))

        @printAct = Qt::Action.new(tr("&Print..."), self)
        @printAct.shortcut = Qt::KeySequence.new(tr("Ctrl+P"))
        @printAct.enabled = false
        connect(@printAct, SIGNAL('triggered()'), self, SLOT('print()'))

        @exitAct = Qt::Action.new(tr("E&xit"), self)
        @exitAct.shortcut = Qt::KeySequence.new(tr("Ctrl+Q"))
        connect(@exitAct, SIGNAL('triggered()'), self, SLOT('close()'))

        @zoomInAct = Qt::Action.new(tr("Zoom &In (25%)"), self)
        @zoomInAct.shortcut = Qt::KeySequence.new(tr("Ctrl++"))
        @zoomInAct.enabled = false
        connect(@zoomInAct, SIGNAL('triggered()'), self, SLOT('zoomIn()'))

        @zoomOutAct = Qt::Action.new(tr("Zoom &Out (25%)"), self)
        @zoomOutAct.shortcut = Qt::KeySequence.new(tr("Ctrl+-"))
        @zoomOutAct.enabled = false
        connect(@zoomOutAct, SIGNAL('triggered()'), self, SLOT('zoomOut()'))

        @normalSizeAct = Qt::Action.new(tr("&Normal Size"), self)
        @normalSizeAct.shortcut = Qt::KeySequence.new(tr("Ctrl+S"))
        @normalSizeAct.enabled = false
        connect(@normalSizeAct, SIGNAL('triggered()'), self, SLOT('normalSize()'))

        @fitToWindowAct = Qt::Action.new(tr("&Fit to Window"), self)
        @fitToWindowAct.enabled = false
        @fitToWindowAct.checkable = true
        @fitToWindowAct.shortcut = Qt::KeySequence.new(tr("Ctrl+F"))
        connect(@fitToWindowAct, SIGNAL('triggered()'), self, SLOT('fitToWindow()'))

        @aboutAct = Qt::Action.new(tr("&About"), self)
        connect(@aboutAct, SIGNAL('triggered()'), self, SLOT('about()'))

        @aboutQtAct = Qt::Action.new(tr("About &Qt"), self)
        connect(@aboutQtAct, SIGNAL('triggered()'), $qApp, SLOT('aboutQt()'))
end

createMenus() click to toggle source

# File examples/widgets/imageviewer/imageviewer.rb, line 175
def createMenus()
        @fileMenu = Qt::Menu.new(tr("&File"), self)
        @fileMenu.addAction(@openAct)
        @fileMenu.addAction(@printAct)
        @fileMenu.addSeparator()
        @fileMenu.addAction(@exitAct)

        @viewMenu = Qt::Menu.new(tr("&View"), self)
        @viewMenu.addAction(@zoomInAct)
        @viewMenu.addAction(@zoomOutAct)
        @viewMenu.addAction(@normalSizeAct)
        @viewMenu.addSeparator()
        @viewMenu.addAction(@fitToWindowAct)

        @helpMenu = Qt::Menu.new(tr("&Help"), self)
        @helpMenu.addAction(@aboutAct)
        @helpMenu.addAction(@aboutQtAct)

        menuBar().addMenu(@fileMenu)
        menuBar().addMenu(@viewMenu)
        menuBar().addMenu(@helpMenu)
end

fitToWindow() click to toggle source

# File examples/widgets/imageviewer/imageviewer.rb, line 106
def fitToWindow()
        fitToWindow = @fitToWindowAct.checked?
        @scrollArea.widgetResizable = fitToWindow
        if !fitToWindow
                @imageLabel.adjustSize()
        end

        updateActions()
end

normalSize() click to toggle source

# File examples/widgets/imageviewer/imageviewer.rb, line 101
def normalSize()
        @imageLabel.adjustSize()
        @scaleFactor = 1.0
end

open() click to toggle source

# File examples/widgets/imageviewer/imageviewer.rb, line 57
def open()
        fileName = Qt::FileDialog::getOpenFileName(self,
                                                                        tr("Open File"), Qt::Dir.currentPath())
        if !fileName.nil?
                image = Qt::Image.new(fileName)
                if image.nil?
                        Qt::MessageBox.information(self, tr("Image Viewer"),
                                                                        tr("Cannot load %s." % fileName))
                        return
                end
                @imageLabel.pixmap = Qt::Pixmap.fromImage(image)
                @scaleFactor = 1.0

                @printAct.enabled = true
                @fitToWindowAct.enabled = true
                updateActions()

                if !@fitToWindowAct.checked?
                        @imageLabel.adjustSize
                end
        end
end

print() click to toggle source

# File examples/widgets/imageviewer/imageviewer.rb, line 80
def print()
        dialog = Qt::PrintDialog.new(@printer, self)
        if dialog.exec
                painter = Qt::Painter.new(@printer)
                rect = painter.viewport
                size = @imageLabel.pixmap.size
                size.scale(rect.size(), Qt::KeepAspectRatio)
                painter.viewport = Qt::Rect.new(rect.x, rect.y, size.width, size.height)
                painter.window = @imageLabel.pixmap.rect
                painter.drawPixmap(0, 0, @imageLabel.pixmap)
        end
end

scaleImage(factor) click to toggle source

# File examples/widgets/imageviewer/imageviewer.rb, line 204
def scaleImage(factor)
        @scaleFactor *= factor
        @imageLabel.resize(@imageLabel.pixmap().size() * @scaleFactor)

        adjustScrollBar(@scrollArea.horizontalScrollBar(), factor)
        adjustScrollBar(@scrollArea.verticalScrollBar(), factor)

        @zoomInAct.enabled = @scaleFactor < 3.0
        @zoomOutAct.enabled = @scaleFactor > 0.333
end

updateActions() click to toggle source

# File examples/widgets/imageviewer/imageviewer.rb, line 198
def updateActions()
        @zoomInAct.enabled = !@fitToWindowAct.checked?
        @zoomOutAct.enabled = !@fitToWindowAct.checked?
        @normalSizeAct.enabled = !@fitToWindowAct.checked?
end

zoomIn() click to toggle source

# File examples/widgets/imageviewer/imageviewer.rb, line 93
def zoomIn()
        scaleImage(1.25)
end

zoomOut() click to toggle source

# File examples/widgets/imageviewer/imageviewer.rb, line 97
def zoomOut()
        scaleImage(0.8)
end