UserView : View : QObject : Object

Description

An empty view on which you can draw using the Pen class.

This view displays and does nothing by itself, but allows you to define how it will be drawn, and expects you to define its entire mode of interaction using mouse, key, and drag and drop actions.

To define how the view is drawn you set the -drawFunc variable to a Function within which you can use the Pen class to draw graphical primitives, such as lines, rectangles, ellipses, curves, and also text.

This class offers convenient mechanisms for creating animations, that is, to automatically redraw itself in regular time intervals. See the Animation section of this document.

For a guide to using this view, see Introduction to GUI: Custom views.

Class Methods

Inherited class methods

Undocumented class methods

UserView.new(parent, bounds)

UserView.qtClass

UserView.sizeHint

Instance Methods

Drawing

.drawFunc

.drawFunc = aFunction

.background

.background = color

.drawingEnabled

.drawingEnabled = boolean

.clearOnRefresh

.clearOnRefresh = boolean

.clearDrawing

Animation

.animate

.animate = bool

.frameRate

.frameRate = fps

.frame

Actions

The UserView by itself does not respond to any interaction by the user. You can define the modes of interaction entirely on your own using mouse and keyboard actions. See Actions and Hooks for detailed explanation.

Note that there is no default mode of interaction with the UserView, so View: -action will never be triggered, if you don't implement that yourself.

Inherited instance methods

Undocumented instance methods

.action

.action = func

.doDrawFunc

.draw

.drawHook = func

Examples

'Introduction to GUI' contains an example with elaborate explanation on how to use UserView. Below are further examples.

Basic Usage

Resize the window or click on the UserView to refresh the drawing:( w=Window.new; v=UserView(w, w.view.bounds.insetBy(50,50)); v.resize = 5; v.background_(Color.rand); v.drawFunc={|uview| Pen.moveTo(0@uview.bounds.height.rand); Pen.lineTo(uview.bounds.width@uview.bounds.height.rand); Pen.stroke; }; v.mouseDownAction={v.refresh}; w.front; )

Coordinates are relative to the UserView. Try resizing the window:( var func; func = {|me| Pen.use{ 10.do{ Color.red(rrand(0.0, 1), rrand(0.0, 0.5)).set; Pen.addArc((400.exprand(2))@(100.rand), rrand(10, 100), 2pi.rand, pi); Pen.perform([\stroke, \fill].choose); } } }; w = Window.new("DrawFunc Examples").front; w.view.background_(Color.white); 3.do{|i| v = UserView(w, Rect(20+(i*120), 100, 100, 100)) .drawFunc_(func); v.resize=3; // the func coordinates ar valid even though the view move on resize v.background_(Color.rand); }; w.refresh; )

Responding to mouse clicks and movement

Using mouse actions you can make UserView change the way it is drawn in response to mouse interaction. The sequence of examples below will guide you through the various possibilities.

Clicking and moving the mouse on each of the painted squares in the following example will redraw them differently. See interpreter output for posted information that you can use in the mouse actions.// drag some circles ( var w, r, u; var clicked, relativeWhere; r = { Rect(300.rand, 300.rand, 110, 110) } ! 4; w = Window.new.front; u = UserView(w, Rect(0, 0, 400, 400)); u.drawFunc = { r.do { |x, i| Pen.addOval(x); // wie addRect Pen.color = Color.hsv(0.9 * (1/(i+1)), 0.6, 1); Pen.draw; }; }; u.mouseDownAction = { |v, x, y| r.do { |rect, i| if(rect.contains(Point(x, y))) { clicked = i; relativeWhere = Point(x, y) - rect.origin; }; }; }; u.mouseMoveAction = { |v, x, y| var rect; if(clicked.notNil) { rect = r.at(clicked); r.put(clicked, rect.origin = Point(x, y) - relativeWhere); w.refresh; } }; u.mouseUpAction = { clicked = nil; } ) // draw some random shapes ( var drawFunc, mouseDownFunc, mouseUpFunc, mouseMoveFunc, sat = 0, startX; drawFunc = {|me| Pen.use{ 10.do{ Color.red(rrand(0.0, 1), rrand(0.3, 0.8)).set; Pen.addArc((400.exprand(2))@(100.rand), rrand(10, 50), 2pi.rand, pi); Pen.perform([\stroke, \fill].choose); } } }; mouseDownFunc = {|me, x, y, mod| startX = x; postf("begin path: x=% realtive mouse coordinates:%\n",startX, x@y); }; mouseUpFunc = {|me, x, y, mod| postf("end path: (startX-x)==% mouse coordinates:%\n",(startX-x), x@y); }; mouseMoveFunc = {|me, x, y, mod| sat = ((startX-x)/100); (x@y).postln; me.refresh; }; w = Window.new.front; w.view.background_(Color.white); 3.do{|i| v = UserView(w, Rect(20+(i*120), 100, 100, 100)); v.background_(Color.rand); v.drawFunc = drawFunc; v.mouseDownAction = mouseDownFunc; v.mouseUpAction = mouseUpFunc; v.mouseMoveAction = mouseMoveFunc; }; w.refresh; )

The following example uses the -clearOnRefresh option to prevent the UserView from clearing its contents when redrawn. Clicking and moving the mouse within each square will draw ever more arcs on top of each other.( var func, views; func = {|me| Pen.use{ 1.do{ Color( rrand(0.0, 1), rrand(0.0,0.2), rrand(0.0, 0.8), rrand(0.4, 0.8) ).set; Pen.addArc((400.exprand(2))@(100.rand), rrand(10, 50), 2pi.rand, pi); Pen.perform([\stroke, \fill].choose); } } }; w = Window.new("DrawFunc Examples").front; w.view.background_(Color.white); views = {|i| v = UserView(w, Rect(20+(i*120), 100, 100, 100)); v.background = Color.rand; v.drawFunc = func; v.mouseMoveAction = {|me| me.refresh }; v.clearOnRefresh_(false); } ! 3; w.refresh; )

The following example uses the -clearOnRefresh option to keep the old contents when redrawn, allowing you to draw a line which follows the mouse cursor by clicking and dragging on the view.

It also uses the mouse position to compute the color of the line.( var w, txt, lines, points, drawLine; drawLine = { |points, bounds| var p0; points.do { |p,i| if(i == 0){ p0 = p; }{ Pen.moveTo(p0); Pen.lineTo(p); Color( (p.x/bounds.width).clip(0,1), 1.0-(p.x/bounds.width).clip(0,1), (p.y/bounds.height).clip(0,1) ).set; Pen.stroke; p0 = p; } }; }; w = Window("draw on me", Rect(128, 64, 340, 360)); v = UserView(w,w.view.bounds) .clearOnRefresh_(false) .mouseDownAction_({|v,x,y| points = [x@y]; }) .mouseMoveAction_({|v,x,y| points = points.add(x@y); v.refresh; }) .mouseUpAction_({|v,x,y| points = points.add(x@y); lines = lines.add(points); points = nil; v.refresh; }) .background_(Color.white) .drawFunc_{|me| var r = me.bounds; Pen.use { Pen.width = 1; Color.black.set; lines.do { |linePoints| drawLine.value(linePoints, r); }; lines = nil; drawLine.value(points, r); if( points.size > 0 ) { points = [points.last] }; }; }; w.front; )

Animation

The following is an animation with mouse interaction. Click and drag in the view to move the center of the rotating object.( var width = 400, height = 400, mx = 0, my = 0, pt, r; w = Window("animation and mouse interaction", Rect(100, 200, width, height), false); u = UserView(w, Rect(0, 0, width, height)); u.background = Color.black; u.animate = true; //animate this view // allocate data in advance, for optimization: pt = Point(); r = Rect(); u.drawFunc = { Pen.fillColor = Color.green; Pen.stringAtPoint(u.frameRate.asString, Point(10, 10)); // display frame rate Pen.stringAtPoint(u.frame.asString, Point(10, 30)); // display frame counter Pen.color = Color.white; pt.x=mx; pt.y=my; 100.do{|i| Pen.moveTo(pt); pt.x = sin(u.frame*0.04.neg+i)*(5*i)+mx; //use .frame to drive animation pt.y = cos(u.frame*0.05+i)*(5*i)+my; r.left=pt.x; r.top=pt.y; r.width=i; r.height=i; Pen.lineTo(pt); Pen.fillStroke; Pen.addOval(r); Pen.fillStroke; }; }; u.mouseDownAction = {|v, x, y| mx = x; my = y; }; u.mouseMoveAction = u.mouseDownAction; w.front; ) u.animate = false; //animation can be paused and resumed u.animate = true; w.close; //stops animation

A simple ball animation:( var width = 400, height = 400, xspeed = 3, yspeed = 2, x = width*0.5, y = height*0.5; w = Window("ball", Rect(100, 200, width, height)); u = UserView(w, Rect(0, 0, width, height)); u.background = Color.black; u.animate = true; u.drawFunc = { if(x<0 or:{x>width}, {xspeed = 0-xspeed}); if(y<0 or:{y>height}, {yspeed = 0-yspeed}); x = x+xspeed; y = y+yspeed; Pen.fillColor = Color.white; Pen.fillOval(Rect.aboutPoint(Point(x, y), 8, 8)); }; w.front; ) ( //replace the drawFunc above while running u.drawFunc = { Pen.fillColor = Color.red; Pen.fillOval(Rect(200, 200, sin(u.frame*0.031)*200, sin(u.frame*0.044)*200)); Pen.fillOval(Rect(200, 200, sin(u.frame*0.052)*200, sin(u.frame*0.065)*200)); Pen.fillOval(Rect(200, 200, sin(u.frame*0.073)*200, sin(u.frame*0.086)*200)); } ) //close the window to stop w.close;

An animation that makes a good use of the -clearOnRefresh option to keep the old contents when redrawing.( var width = 640, height = 480, w, theta = 0, drawFunc; w = Window( "trails", Rect( 128, 64, width, height ), false ); drawFunc = { arg view; var x = 20 * sin( theta ), y = 42 * cos( theta ); theta = theta + 0.01; //draw a semitransparent rect filling the screen: Pen.fillColor_( Color.red( 0.2, 0.1 )); Pen.fillRect( Rect( 0, 0, width, height )); Pen.strokeColor_( Color.white ); Pen.translate( width * 0.5, height * 0.5 ); 6.do { arg i; Pen.rotate( theta * (1 - (i / 6)) ); Pen.scale( 0.7 + (i * 0.4), 0.4 + (i * 0.5) ); Pen.strokeOval( Rect.aboutPoint( Point( x, y ), 60, 40 )); }; }; x = UserView( w, Rect( 10, 10, width - 20, height - 20 )) .canFocus_( false ) .drawFunc_( drawFunc ) .clearOnRefresh_( false ); w.front; x.animate = true )

Usage of refreshInRect(aRect)

The refreshInRect method constrains the receiver's refresh area to the rectangle passed in aRect. You may use Quartz Debug's flash screen updates to see the refresh area of the view( var userView, win, blob = Rect(0, 0, 50, 50), trackblob=false, pmouse; a = SCImage.new("/Library/Desktop Pictures/Ripples Blue.jpg"); win = SCWindow.new("refreshInRect Test", Rect(400, 400, 600, 200), scroll:true).front; win.onClose_({ a.free; }); userView = SCUserView(win, Rect(10,10,2000,800)) .backgroundImage_(a, 5) .drawFunc_({|me| Color.blue.setFill; Pen.fillRect(blob); }) .mouseDownAction_({|v, x, y, mod| pmouse = x@y; trackblob = blob.containsPoint(pmouse); }) .mouseUpAction_({|v, x, y, mod| trackblob = false; }) .mouseMoveAction_({|v, x, y, mod| var refresh, mouse, delta; mouse = x@y; if(trackblob, { refresh = blob.copy; delta = mouse-pmouse; blob = blob.moveBy(delta.x, delta.y); refresh = refresh.union(blob); v.refreshInRect(refresh); }); pmouse = mouse; }); blob = blob.moveBy(userView.bounds.left, userView.bounds.top); userView.bounds.postln; )