Difference between revisions of "Flags with Lines"

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Line 1: Line 1:
<pre id='shellbody'>
<pre id='shellbody' data-qtp='canvas'></pre>
<div style='background:silver;padding:5px'>
Get on with the programming, don't pause to look at this worked example: [[Road Sign Square]]
<canvas id='usr' width=--snippet-w-- height=--snippet-h--></canvas>
<canvas id='ans' width=--snippet-w-- height=--snippet-h-- style='display:none'></canvas>
</div>
</pre>
 
<pre id='shelljs'>
--snippet-usr--
drawFlag(document.getElementById('usr').getContext('2d'));
(()=>{
  --snippet-ans--
  drawFlag(document.getElementById('ans').getContext('2d'));
})();
let [a,b] = ['usr','ans']
    .map(id=>document.getElementById(id))
    .map(elem=>elem.getContext('2d').getImageData(0,0,elem.width,elem.height))
let diff = a.data.map((v,i) => v===b.data[i]?1:0).reduce((acc,v)=>acc+v,0)*100/a.data.length;
let fb = document.createElement('div');
fb.innerText = `Score: ${diff.toFixed(1)}`;
document.body.appendChild(fb);
fetch(`/reportProgress.php?uid=--snippet-uid--&qid=--snippet-qid--&score=${diff}`);
</pre>
==England==
==England==


<div class=qu data-height="90" data-width="150" title="England">
<div class=qu data-height="90" data-width="150">
The English flag is the cross of St. George. This is a red cross on a white
The English flag is the cross of St. George. This is a red cross on a white
background.
background .
*The line thickness should be 18.
*The line thickness should be 18.  
[[Image:flagengland.png]]
[[Image:flagengland.png]]
<pre class=usr>
<pre class=usr>
Line 36: Line 15:
   ctx.strokeStyle = 'red';
   ctx.strokeStyle = 'red';
   ctx.lineWidth = 18;
   ctx.lineWidth = 18;
  ctx.beginPath();
   ctx.moveTo(0,45);
   ctx.moveTo(0,45);
   ctx.lineTo(150,45);
   ctx.lineTo(150,45);
Line 49: Line 27:
   ctx.strokeStyle = 'red';
   ctx.strokeStyle = 'red';
   ctx.lineWidth = 18;
   ctx.lineWidth = 18;
  ctx.beginPath();
   ctx.moveTo(0,45);
   ctx.moveTo(0,45);
   ctx.lineTo(150,45);
   ctx.lineTo(150,45);
Line 60: Line 37:


==Scotland==
==Scotland==
<div class=qu data-height="90" data-width="150" title="Scotland" data-cols='40'>
<div class=qu data-height="90" data-width="150" data-cols='40'>
The cross of St. Andrew shows diagonal lines on a blue background.<br/>
The cross of St. Andrew shows diagonal lines on a blue background.<br/>
*Complete the flag by drawing the other diagonal  line.
*Complete the flag by drawing the other diagonal  line.
Line 71: Line 48:
   ctx.fillRect(0,0,150,90);
   ctx.fillRect(0,0,150,90);
   ctx.strokeStyle = 'red';
   ctx.strokeStyle = 'red';
   ctx.lineWidth = 18;
   ctx.lineWidth = 10;
  ctx.beginPath();
   ctx.moveTo(0,0);
   ctx.moveTo(0,0);
   ctx.lineTo(150,90);
   ctx.lineTo(150,90);
Line 85: Line 61:
   ctx.strokeStyle = 'white';
   ctx.strokeStyle = 'white';
   ctx.lineWidth = 18;
   ctx.lineWidth = 18;
  ctx.beginPath();
   ctx.moveTo(0,0);
   ctx.moveTo(0,0);
   ctx.lineTo(150,90);
   ctx.lineTo(150,90);
Line 96: Line 71:


==Botswana==
==Botswana==
<div class=qu data-width="150" data-height="100" title="Botswana">
<div class=qu data-width="150" data-height="100">
The flag of Botswana has a black stripe on a white stripe on a blue background.
The flag of Botswana has a black stripe on a white stripe on a blue background.


Line 119: Line 94:
   ctx.strokeStyle = 'white';
   ctx.strokeStyle = 'white';
   ctx.lineWidth = 30;
   ctx.lineWidth = 30;
  ctx.beginPath();
   ctx.moveTo(0,50);
   ctx.moveTo(0,45);
   ctx.lineTo(150,50);
   ctx.lineTo(150,45);
   ctx.stroke();
   ctx.stroke();
   ctx.strokeStyle = 'black';
   ctx.strokeStyle = 'black';
   ctx.lineWidth = 20;
   ctx.lineWidth = 20;
   ctx.beginPath();
   ctx.moveTo(0,50);
  ctx.lineTo(150,50);
  ctx.stroke();
}
</pre>
</div>
 
==Iceland==
<div class=qu data-width="125" data-height="90">
 
[[Image:flagiceland.png|border]]
* 125 by 90
* The white cross is 20 wide
* The red cross is 10 wide
* The cross line intersect at (45, 45)
 
<pre class=usr>
function drawFlag(ctx)
{
}
</pre>
<pre class=ans>
function drawFlag(ctx)
{
  ctx.fillStyle = 'blue';
  ctx.fillRect(0,0,125,90);
  ctx.strokeStyle = 'white';
  ctx.lineWidth = 20;
  ctx.moveTo(45,0);
  ctx.lineTo(45,90);
   ctx.moveTo(0,45);
   ctx.moveTo(0,45);
   ctx.lineTo(150,45);
   ctx.lineTo(125,45);
  ctx.stroke();
  ctx.strokeStyle = 'red';
  ctx.lineWidth = 10;
  ctx.moveTo(45,0);
  ctx.lineTo(45,90);
  ctx.moveTo(0,45);
  ctx.lineTo(125,45);
   ctx.stroke();
   ctx.stroke();
}
}
</pre>
</pre>
<shell lang="java" className="Flag" import="shells.xml#raster"/>
</div>
</div>


==Trinidad and Tobago==
==Trinidad and Tobago==
<div class=qu height="100" width="150" imgOut="flag.png" className="Raster" title="Trinidad and Tobago">
<div class=qu height="100" width="150">
We can start and end lines outside the confines of the surface.
We can start and end lines outside the confines of the surface.
*The white line has width 35
*The white line has width 35
Line 150: Line 159:
   ctx.moveTo(0,-25);
   ctx.moveTo(0,-25);
   ctx.lineTo(75,50);
   ctx.lineTo(75,50);
  ctx.stroke();
}
}
</pre>
</pre>
Line 160: Line 170:
   ctx.strokeStyle = 'white';
   ctx.strokeStyle = 'white';
   ctx.moveTo(0,-25);
   ctx.moveTo(0,-25);
   ctx.lineTo(75,50);
   ctx.lineTo(150,125);
  ctx.stroke();
  ctx.lineWidth = 25;
  ctx.strokeStyle = 'black';
  ctx.moveTo(0,-25);
  ctx.lineTo(150,125);
  ctx.stroke();
}
}
</pre>
</pre>
</div>
</div>

Latest revision as of 16:31, 5 January 2023



Get on with the programming, don't pause to look at this worked example: Road Sign Square





England




The English flag is the cross of St. George. This is a red cross on a white
background .



  • The line thickness should be 18.


Flagengland.png



function drawFlag(ctx)
{
  ctx.fillStyle = 'white';
  ctx.fillRect(0,0,150,90);
  ctx.strokeStyle = 'red';
  ctx.lineWidth = 18;
  ctx.moveTo(0,45);
  ctx.lineTo(150,45);
  ctx.stroke();
}



function drawFlag(ctx)
{
  ctx.fillStyle = 'white';
  ctx.fillRect(0,0,150,90);
  ctx.strokeStyle = 'red';
  ctx.lineWidth = 18;
  ctx.moveTo(0,45);
  ctx.lineTo(150,45);
  ctx.moveTo(75,0);
  ctx.lineTo(75,90);
  ctx.stroke();
}





Scotland




The cross of St. Andrew shows diagonal lines on a blue background.




  • Complete the flag by drawing the other diagonal  line.
    • 

  • The white lines should be slightly thicker - try 18.


Flagscotland.png



function drawFlag(ctx)
{
  ctx.fillStyle = 'white';
  ctx.fillRect(0,0,150,90);
  ctx.strokeStyle = 'red';
  ctx.lineWidth = 10;
  ctx.moveTo(0,0);
  ctx.lineTo(150,90);
  ctx.stroke();
}



function drawFlag(ctx)
{
  ctx.fillStyle = 'blue';
  ctx.fillRect(0,0,150,90);
  ctx.strokeStyle = 'white';
  ctx.lineWidth = 18;
  ctx.moveTo(0,0);
  ctx.lineTo(150,90);
  ctx.moveTo(0,90);
  ctx.lineTo(150,0);
  ctx.stroke();
}





Botswana




The flag of Botswana has a black stripe on a white stripe on a blue background.

Flagbotswana.png



  • The flag is 150 by 100
    • 

  • The white stripe behind the black one has width 30
    • 

  • The black stripe has width 20
    • 

  • The pale blue has rgb: '#6EB6ED'


function drawFlag(ctx)
{
  ctx.fillStyle = '#6EB6ED';
  ctx.fillRect(0,0,150,100);
}



function drawFlag(ctx)
{
  ctx.fillStyle = '#6EB6ED';
  ctx.fillRect(0,0,150,100);
  ctx.strokeStyle = 'white';
  ctx.lineWidth = 30;
  ctx.moveTo(0,50);
  ctx.lineTo(150,50);
  ctx.stroke();
  ctx.strokeStyle = 'black';
  ctx.lineWidth = 20;
  ctx.moveTo(0,50);
  ctx.lineTo(150,50);
  ctx.stroke();
}





Iceland




Flagiceland.png



  • 125 by 90
    • 

  • The white cross is 20 wide
    • 

  • The red cross is 10 wide
    • 

  • The cross line intersect at (45, 45)


function drawFlag(ctx)
{
}



function drawFlag(ctx)
{
  ctx.fillStyle = 'blue';
  ctx.fillRect(0,0,125,90);
  ctx.strokeStyle = 'white';
  ctx.lineWidth = 20;
  ctx.moveTo(45,0);
  ctx.lineTo(45,90);
  ctx.moveTo(0,45);
  ctx.lineTo(125,45);
  ctx.stroke();
  ctx.strokeStyle = 'red';
  ctx.lineWidth = 10;
  ctx.moveTo(45,0);
  ctx.lineTo(45,90);
  ctx.moveTo(0,45);
  ctx.lineTo(125,45);
  ctx.stroke();
}





Trinidad and Tobago




We can start and end lines outside the confines of the surface.



  • The white line has width 35
    • 

  • The black line has width 25


Flagtrinidad.png



function drawFlag(ctx)
{
  ctx.fillStyle = 'red';
  ctx.fillRect(0,0,150,100);
  ctx.lineWidth = 35;
  ctx.strokeStyle = 'white';
  ctx.moveTo(0,-25);
  ctx.lineTo(75,50);
  ctx.stroke();
}



function drawFlag(ctx)
{
  ctx.fillStyle = 'red';
  ctx.fillRect(0,0,150,100);
  ctx.lineWidth = 35;
  ctx.strokeStyle = 'white';
  ctx.moveTo(0,-25);
  ctx.lineTo(150,125);
  ctx.stroke();
  ctx.lineWidth = 25;
  ctx.strokeStyle = 'black';
  ctx.moveTo(0,-25);
  ctx.lineTo(150,125);
  ctx.stroke();
}











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