c# - Flip coordinates when drawing set of rectangles -

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i trying draw set of squares origin(0,0) of squares in top left corner , wanted squares render bottom right corner, , found code flip co ordinates, nothing rendering on winform.

i know have gone wrong in height attribute of translatetransform. dont why height required trying draw set of 2d squares.

i tried hardcoding height attribute still of no use.

public void scaletransformfloat(painteventargs e,list<square> lstsquare)     {         int height = 10;         // begin graphics container         graphicscontainer containerstate = e.graphics.begincontainer();          // flip y-axis         e.graphics.scaletransform(1.0f, -1.0f);          // translate drawing area accordingly         //         e.graphics.translatetransform(0.0f, -(float)height);          // whatever draw (using graphics context) appear                // though (0,0) @ bottom left corner      //user-defined function draw square             drawsquare(e,lstsquare);         // end graphics container         e.graphics.endcontainer(containerstate);       }

method draw set of squares

  public void drawsquare(painteventargs e,list<square> lstsquare)     {       foreach(square s in lstsquare){         e.graphics.drawrectangle(pens.black, 0,0 ,s.m_side, s.m_side);       }     }

when doing matrix operation transformations order matter.

in case need either translate first, scale/flip or reverse direction of translation. code seems right.

the height not 3d height. total height of target control want draw on.

imagine laying sheet of paper on control; control viewport. imagine flipping paper topwise top left edge. has left viewport. need move down. distance? answer: paper's height..

your code has height = 10 pixels. not size of control, right? maybe comes code copied; there meant form's height. if want draw on form (usually not idea), delete line int height = 10;!

let's simple example: draw few rectangles onto panel:

enter image description here

private void panel1_paint(object sender, painteventargs e) {     if (checkbox1.checked)     {         e.graphics.scaletransform(1, -1);         e.graphics.translatetransform(0, -panel1.height);     }     e.graphics.drawrectangle(pens.violet, 1, 1, 33, 33);     e.graphics.drawrectangle(pens.orangered, 11, 11, 133, 55);     e.graphics.drawrectangle(pens.magenta, 44, 11, 233, 77);     e.graphics.drawrectangle(pens.olive, 55, 44, 33, 99); }  private void checkbox1_checkedchanged(object sender, eventargs e) {     panel1.invalidate(); }

after checking checkbox result flipped:

enter image description here

also note drawsquare draws squares @ same location (0,0). not sure if want..

final note: drawrectangle has nasty habit of overdrawing botton , right sides 1 pixel. after changing first loaction (1,1) (0,0) (then) bottom side cut off. might consider translating graphics coodinates 1 pixel less..


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