Learn more about GDI + [34]: tgppen-scale and transform the paint brush-scaletransform

In this example:

Code File:

Unit unit1; interfaceuses windows, messages, sysutils, variants, classes, graphics, controls, forms, dialogs, stdctrls, comctrls; Type tform1 = Class (tform) trackbar1: ttrackbar; trackbar2: ttrackbar; Procedure procedure (Sender: tobject); Procedure trackbar1change (Sender: tobject); Procedure trackbar2change (Sender: tobject); end; var form1: tform1; implementation {$ R *. DFM} uses gdipobj, gdipapi; Procedure upload (Sender: tobject); begin trackbar1.showselrange: = false; trackbar1.height: = 20; trackbar1.min: = 1; trackbar1.max: = 100; trackbar1.position: = 10; trackbar2.showselrange: = false; trackbar2.height: = 20; trackbar2.min: = 1; trackbar2.max: = 100; trackbar2.position: = 10; end; Procedure tform1.formpaint (Sender: tobject ); vaR G: tgpgraphics; P: tgppen; R: trect; begin G: = tgpgraphics. create (canvas. handle); P: = tgppen. create (aclbrown, 3); p. scaletransform (trackbar1.position/10, trackbar2.position/10); R: = clientrect; inflaterect (R,-30,-30); offsetrect (R, 0,-10); G. drawellipse (p, makerect (R); p. free; G. free; end; Procedure tform1.trackbar1change (Sender: tobject); begin repaint; end; Procedure tform1.trackbar2change (Sender: tobject); begin repaint; end.
 
   
 

Form file:

 
Object form1: tform1 left = 0 Top = 0 caption = 'form1' clientheight = 196 clientwidth = 296 color = clbtnface font. charset = default_charset font. color = clwindowtext font. height =-11 font. name = 'tahoma 'font. style = [] oldcreateorder = false position = pow.topcenter oncreate = formcreate onpaint = formpaint pixelsperinch = 96 textheight = 13 object trackbar1: ttrackbar left = 2 Top = 172 width = 143 Height = 45 taborder = 0 onchange = trackbar1change end object trackbar2: ttrackbar left = 151 Top = 172 width = 143 Height = 45 taborder = 1 onchange = trackbar2change endend