require 'Qt' class Hello < TQt::Widget signals 'clicked()' slots 'animate()' # Constructs a Hello widget. Starts a 40 ms animation timer def initialize (text) super() @b = 0 @text = text @sin_tbl = [0, 38, 71, 92, 100, 92, 71, 38, 0, -38, -71, -92, -100, -92, -71, -38] timer = TQt::Timer.new(self); connect(timer, TQ_SIGNAL('timeout()'), TQ_SLOT('animate()')) timer.start(40); resize(260, 130) end # This slot is called each time the timer fires. def animate @b = (@b + 1) & 15 repaint(false) end # Handles mouse button release events for the Hello widget. # # We emit the clicked() signal when the mouse is released inside # the widget. def mouseReleaseEvent(e) if (rect.contains(e.pos)) emit clicked end end # Handles paint events for the Hello widget. # # Flicker-free update. The text is first drawn in the pixmap and the # pixmap is then blt'ed to the screen. def paintEvent(e) if @text.empty? return end # 1: Compute some sizes, positions etc. fm = fontMetrics w = fm.width(@text) + 20 h = fm.height * 2 pmx = width/2 - w/2 pmy = height/2 - h/2 # 2: Create the pixmap and fill it with the widget's background pm = TQt::Pixmap.new(w, h) pm.fill(self, pmx, pmy) # 3: Paint the pixmap. Cool wave effect p = TQt::Painter.new; x = 10 y = h/2 + fm.descent i = 0 p.begin(pm) p.setFont(font) for i in 0..@text.size-1 j = (@b+i) & 15 p.setPen(TQt::Color.new((15-j)*16,255,255,TQt::Color.Hsv) ) p.drawText( x, y-@sin_tbl[j]*h/800, @text[i,1], 1 ) x += fm.width(@text[i,1]) end p.end #4: Copy the pixmap to the Hello widget bitBlt(self, pmx, pmy, pm) end end