[Solved] How to make a special brush.style ?
lazarus / 39-Graphics

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loaded · 2019-11-01 07:19

Hello, dear friends.
When drawing inside the closed polygons with the following code;
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i  
canvas.Brush.Color:=clBlack;                      //bsHorizontal     
               //bsVertical                      //bsFDiagonal       
             //bsBDiagonal                      //bsCross            
        //bsDiagCross  canvas.Brush.Style:=bsCross; 
canvas.Rectangle(canvas.ClipRect);  Styles, I can change.
I need the styles in the picture.
I'd appreciate it if he could help me with this. Respects.

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wp · 2019-11-01 10:38

Create (or load) a bitmap of the repeated elemental cell, assign it to
the Bitmap property of the Brush and set the Brush.Style to bsImage
(requires FPCanvas in "uses").

A related method using the Brush.Style psPattern and a 32-longword
array for the pattern does not seem to work. At least, I did not find
a way to make it work.

See attached demo.

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loaded · 2019-11-01 11:40

Thank you very much for your wp answer. It expanded my horizon. I've
heard the bitmap method, but I haven't tried it because of my
performance concerns. But I understand the method I'm looking for is
bsPattern. I didn't know this method. Thank you so much for teaching.
By the way, the sample you're sending is working fine. About the
subject ; I'm gonna have to do some trial and error.

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winni · 2019-11-01 13:21

Hi!

You cannot assign a pattern to a brush because the brush has no method
setpattern. This is only present for a pen.

But it is no problem to draw the background with the pen. It is all
drawn to the same canvas.

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i const pat :
array[0..3] of LongWord = (10, 3,1,3);var y : integer;             
begin               Image4.canvas.Pen.Color:= clBlack;             
 Image4.canvas.Pen.Style:= psPattern;             
 Image4.canvas.Pen.SetPattern(pat);                for y := 0 to
Image4.height -1 do                   
 Image4.canvas.line(0,y,Image4.width-1,y);               end;        
                                                              
In the pattern are the different pixel length of the pattern.

Take care:  pattern is an array of longword, so you can put there - by
mistake - a value like
$AAFFAAFF. Dont do that! The application crashes without any error
message.

I think it is because the max size of the canvas is maxSmallInt x
maxSmallInt (32767).

Winni

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loaded · 2019-11-01 13:57

winni thank you very much for your answer.
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TForm1.Button1Click(Sender: TObject);  const  pat : array[0..3] of
LongWord = (16, 16,16,16);begin   
Image1.Canvas.Brush.Color:=clWhite;   
Image1.Canvas.pen.Color:=clWhite;   
Image1.Canvas.Brush.Style:=bsSolid;   
Image1.Canvas.Rectangle(Image1.Canvas.ClipRect);   
Image1.canvas.Pen.Style:= psPattern;   
Image1.canvas.Pen.SetPattern(pat);    Image1.canvas.pen.Color:=clred; 
  Image1.canvas.Pen.Width:=1;   
Image1.canvas.line(0,0,Image1.width,Image1.Height);end;  I tried to
understand the logic of the work by changing the code you sent a
little.
What I don't understand is, why does the method that works with the
pen not work with the brush?
How do I change existing patterns in the brush ?

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wp · 2019-11-01 14:20

See also: https://forum.lazarus.freepascal.org/index.php?topic=35745.0

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winni · 2019-11-01 17:06

!

Dont try to change an existing brush. Create youself  one.

If you want a small checker board do it this way:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i var bmp :
TBitmap;begin        bmp := TBitmap.create;       
bmp.setSize(10,10);        bmp.canvas.brush.color := clWhite;       
bmp.canvas.FillRect(0,0,Image4.Width,Image4.Height);       
bmp.canvas.brush.color := clblack;       
bmp.canvas.FillRect(0,0,4,4);        bmp.canvas.FillRect(5,5,9,9);   
   Image4.canvas.brush.Style:= bsPattern;       
Image4.canvas.brush.Bitmap := bmp;       
Image4.canvas.FillRect(0,0,Image4.width, image4.height);       
bmp.free;      end;  
Keep on brushing!

Winni

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loaded · 2019-11-02 08:07

Your ideas enlightened me a lot. I did what I tried to do.
wp and winni thank you very much. respects.

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TForm1.Button1Click(Sender: TObject);var bmp : TBitmap;begin       
bmp := TBitmap.create;        bmp.setSize(10,10);       
bmp.canvas.brush.color := clWhite;       
bmp.canvas.FillRect(bmp.canvas.ClipRect);       
bmp.canvas.brush.color := clblack;        bmp.canvas.Line(5,2,2,8);  
    bmp.canvas.Line(2,8,8,8);        bmp.canvas.Line(8,8,5,2);       
 Image4.canvas.brush.Color := clWhite;       
Image4.canvas.brush.Style := bsSolid;       
Image4.canvas.FillRect(Image4.Canvas.ClipRect);        
Image4.canvas.brush.Style:= bsPattern;  // add uses FPCanvas       
Image4.canvas.brush.Bitmap := bmp;       
Image4.canvas.Polygon([Point(10,10), Point(585,15),
Point(600,350),Point(55,65)]);        bmp.free;end;