Class: ScribbleArea

Inherits:
Qt::Widget show all
Defined in:
ext/ruby/qtruby/examples/widgets/scribble/scribblearea.rb,
ext/ruby/qtruby/examples/qtscribble/scribble.rb

Overview

** ** Copyright © 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 [email protected]. ** ** 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

Instance Method Summary collapse

Methods inherited from Qt::Widget

#raise

Methods inherited from Qt::Base

#%, #&, #*, #**, #+, #-, #-@, #/, #<, #<<, #<=, #==, #>, #>=, #>>, #QCOMPARE, #QEXPECT_FAIL, #QFAIL, #QSKIP, #QTEST, #QVERIFY, #QVERIFY2, #QWARN, #^, ancestors, #is_a?, #methods, private_slots, #protected_methods, #public_methods, q_classinfo, q_signal, q_slot, signals, #singleton_methods, slots, #|, #~

Constructor Details

#initialize(parent = nil) ⇒ ScribbleArea

The constructor. Initializes the member variables.



17
18
19
20
21
22
23
24
25
26
27
28
29
30
 
# File 'ext/ruby/qtruby/examples/qtscribble/scribble.rb', line 17

def initialize(parent)
	super(parent)
	# initialize member variables
	@_buffer = Qt::Pixmap.new()
	@_last = Qt::Point.new()
	@_currentcolor = Qt::black
	
	# don't blank the window before repainting
	setAttribute( Qt::WA_NoBackground )
	
	# create a pop-up menu
	@_popupmenu = Qt::Menu.new()
	@_popupmenu.addAction( "&Clear", self, SLOT( "slotClearArea()" ) )
end

Instance Method Details

#clearImage ⇒ Object 



87
88
89
90
91
 
# File 'ext/ruby/qtruby/examples/widgets/scribble/scribblearea.rb', line 87

def clearImage()
	@image.fill(qRgb(255, 255, 255))
	@modified = true
	update()
end

#drawLineTo(endPoint) ⇒ Object 



129
130
131
132
133
134
135
136
137
138
139
140
 
# File 'ext/ruby/qtruby/examples/widgets/scribble/scribblearea.rb', line 129

def drawLineTo(endPoint)
	painter = Qt::Painter.new(@image)
	painter.pen = Qt::Pen.new(Qt::Brush.new(@myPenColor), @myPenWidth, Qt::SolidLine, Qt::RoundCap,
						Qt::RoundJoin)
	painter.drawLine(@lastPoint, endPoint)
	@modified = true

	rad = @myPenWidth / 2
	update(Qt::Rect.new(@lastPoint, endPoint).normalized().adjusted(-rad, -rad, +rad, +rad))
	@lastPoint = endPoint
	painter.end
end

#modified? ⇒ Boolean

Returns:

  • (Boolean) 


67
68
69
 
# File 'ext/ruby/qtruby/examples/widgets/scribble/scribblearea.rb', line 67

def modified?
	return @modified
end

#mouseMoveEvent(event) ⇒ Object

The method is called whenever the usr moves the mouse while the mouse button is pressed. If we had called setMouseTracking(true) before, the method would also be called when the mouse was moved with any button pressed. We know that we haven’t, and thus don’t have to check whether any buttons are pressed.



100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
 
# File 'ext/ruby/qtruby/examples/qtscribble/scribble.rb', line 100

def mouseMoveEvent(event)
	# create a Qt::Painter object for drawing onto the window
	windowpainter = Qt::Painter.new()
	# and another Qt::Painter object for drawing int an off-screen pixmap
	bufferpainter = Qt::Painter.new()
	
	# start painting
	windowpainter.begin( self ) # This painter paints onto the window
	bufferpainter.begin( @_buffer )  # and this one paints in the buffer

	# set a standard pen with the currently selected color
	windowpainter.setPen( @_currentcolor )
	bufferpainter.setPen( @_currentcolor )

	# draw a line in both the window and the buffer
	windowpainter.drawLine( @_last, event.pos() )
	bufferpainter.drawLine( @_last, event.pos() )

	# done with painting
	windowpainter.end()
	bufferpainter.end()

	# remember the current mouse position
	@_last = event.pos()						
end

#mousePressEvent(event) ⇒ Object

This method is called whenever the user presses the mouse over the window. It just records the position of the mouse at the time of the click.



83
84
85
86
87
88
89
 
# File 'ext/ruby/qtruby/examples/qtscribble/scribble.rb', line 83

def mousePressEvent(event)
	if event.button() == RightButton
		@_popupmenu.exec( Qt::Cursor.pos() )
	else
		@_last = event.pos()	# retrieve the coordinates from the event
	end
end

#mouseReleaseEvent(event) ⇒ Object 



106
107
108
109
110
111
 
# File 'ext/ruby/qtruby/examples/widgets/scribble/scribblearea.rb', line 106

def mouseReleaseEvent(event)
	if event.button() == Qt::LeftButton && @scribbling
		drawLineTo(event.pos())
		@scribbling = false
	end
end

#openImage(fileName) ⇒ Object 



41
42
43
44
45
46
47
48
49
50
51
52
53
 
# File 'ext/ruby/qtruby/examples/widgets/scribble/scribblearea.rb', line 41

def openImage(fileName)
	loadedImage = Qt::Image.new
	if !loadedImage.load(fileName)
		return false
	end

	newSize = loadedImage.size().expandedTo(size())
	resizeImage(loadedImage, newSize)
	@image = loadedImage
	@modified = false
	update()
	return true
end

#paintEvent(event) ⇒ Object

This method is called whenever the widget needs painting, for example when it has been obscured and then revealed again.



130
131
132
 
# File 'ext/ruby/qtruby/examples/qtscribble/scribble.rb', line 130

def paintEvent(event)
	bitBlt(self, 0, 0, @_buffer)
end

#penColor ⇒ Object 



71
72
73
 
# File 'ext/ruby/qtruby/examples/widgets/scribble/scribblearea.rb', line 71

def penColor
	return @myPenColor
end

#penColor=(newColor) ⇒ Object 



75
76
77
 
# File 'ext/ruby/qtruby/examples/widgets/scribble/scribblearea.rb', line 75

def penColor=(newColor)
	@myPenColor = newColor
end

#penWidth ⇒ Object 



79
80
81
 
# File 'ext/ruby/qtruby/examples/widgets/scribble/scribblearea.rb', line 79

def penWidth
	return @myPenWidth
end

#penWidth=(newWidth) ⇒ Object 



83
84
85
 
# File 'ext/ruby/qtruby/examples/widgets/scribble/scribblearea.rb', line 83

def penWidth=(newWidth)
	@myPenWidth = newWidth
end

#resizeEvent(event) ⇒ Object

This method get called whenever the widget needs painting, for example, when it has been obscured and then revealed again.



138
139
140
141
142
143
 
# File 'ext/ruby/qtruby/examples/qtscribble/scribble.rb', line 138

def resizeEvent(event)
	save = Qt::Pixmap.new( @_buffer )
	@_buffer = save.scaled(event.size.width, event.size.height)
	@_buffer.fill( Qt::Color.new(Qt::white) )
	drawPixmap( @_buffer, 0, 0, save )
end

#resizeImage(image, newSize) ⇒ Object 



142
143
144
145
146
147
148
149
150
151
152
153
 
# File 'ext/ruby/qtruby/examples/widgets/scribble/scribblearea.rb', line 142

def resizeImage(image, newSize)
	if image.size == newSize
		return
	end

	newImage = Qt::Image.new(newSize, Qt::Image::Format_RGB32)
	newImage.fill(qRgb(255, 255, 255))
	painter = Qt::Painter.new(newImage)
	painter.drawImage(Qt::Point.new(0, 0), image)
	@image = newImage
	painter.end
end

#saveImage(fileName, fileFormat) ⇒ Object 



55
56
57
58
59
60
61
62
63
64
65
 
# File 'ext/ruby/qtruby/examples/widgets/scribble/scribblearea.rb', line 55

def saveImage(fileName,  fileFormat)
	visibleImage = @image
	resizeImage(visibleImage, size())

	if visibleImage.save(fileName, fileFormat.to_s)
		@modified = false
		return true
	else
		return false
	end
end

#setColor(new_color) ⇒ Object

This slot sets the curren color for the scribble area. It will be connected with the colorChanged( Qt::Color ) signal from the ScribbleWindow.



37
38
39
 
# File 'ext/ruby/qtruby/examples/qtscribble/scribble.rb', line 37

def setColor( new_color )
	@_currentcolor = new_color
end

#slotClearArea ⇒ Object

This slot clears the drawing area by filling the off-screen buffer with white and copying it over to the window.



45
46
47
48
49
50
51
 
# File 'ext/ruby/qtruby/examples/qtscribble/scribble.rb', line 45

def slotClearArea()
	# fill the off screen buffer with plain white
	@_buffer.fill( white )
	
	# and copy it over to the window
	bitBlt( self, 0, 0, @_buffer )
end

#slotLoad(filename) ⇒ Object

This method does the actual loading. It relies on Qt::Pixmap (and the underlying I/O machinery) to determine the filetype.



58
59
60
61
62
63
64
 
# File 'ext/ruby/qtruby/examples/qtscribble/scribble.rb', line 58

def slotLoad( filename )
	if !@_buffer.load( filename )
		Qt::MessageBox.warning( nil, "Load error", "Could not load file" )
	end
		
	repaint()  # refresh the window
end

#slotSave(filename) ⇒ Object

This method does the actual saving. We hard-code the file type as BMP. Unix users might want to replace this with something like XPM.



71
72
73
74
75
 
# File 'ext/ruby/qtruby/examples/qtscribble/scribble.rb', line 71

def slotSave( filename )
	if !@_buffer.save( filename, "BMP" )
		Qt::MessageBox.warning( nil, "Save error", "Could not save file" )
	end
end