1. Attributes of drawing elements
CS-321
4/25/2017
Attributes of drawing elements
All drawn objects have attributes
Color
Line widths
Fill
These are often specified in a structure
Windows: Device Context (DC)
X: Graphics Context (GC)
Abstracted in Qt by a QPainter Object
See
Abstracted in Java’s Swing classes by the Graphics object
Dr. Mark L. Hornick

2. Color [see http://doc.trolltech.com/3.0/qcolor.html]
Specified by Red, Green, and Blue (usually 0-255)
Great for hardware, poor for the user?
Predefined color names (known by Qt)
Predefined names for standard colors
Mapped to RGB values (“Papaya whip”, “Peru”,…)
Fall 2004
CS-321 Dr. Mark L. Hornick

3. Line Attributes [see http://doc.trolltech.com/3.0/qpen.html]
Width
How many pixels wide is a line
Draws rectangle or lines parallel to ideal line
Style
Solid, Dashed, etc.
Line cap
Line end
Fall 2004
CS-321 Dr. Mark L. Hornick

4. Not all styles are supported by Qt.
Line Cap Styles [
Not last
Line endpoint
Butt
Not all styles are supported by Qt.
Round
Projecting
Fall 2004
CS-321 Dr. Mark L. Hornick

5. Line Join Styles [http://doc.trolltech.com/qt.html#PenJoinStyle-enum]
Bevel
Miter
Round
Qt 3 supports all 3 styles.
Fall 2004
CS-321 Dr. Mark L. Hornick

6. Polygon Attributes [see http://doc.trolltech.com/3.0/qbrush.html]
Filling
Inside-Outside Rule
Even-Odd
Non-Zero Winding Number
Solid
Pattern
Fall 2004
CS-321 Dr. Mark L. Hornick