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Paint application in MATLAB

Let’s Paint


This paint application will fill the closed boundary with the specified color.
First, Create image with the well defined boundary value.
                                 

In my application, I created images with boundary/border with black pixel value ie [R,G,B]=[0,0,0] and the rest of the area with white [R,G,B]=[255,255,255].




How to use the application:
1.     Select one image file from the pop up menu.
2.     Select a color and click the image portion to fill the clicked area.
3.     If you need to fill the image portion with another color then click another color button
4.     Click undo button to come back to the previous point.
5.     Click save button to save the file.







This application is based on floodfill algorithm and the same application can be done using bwlabel concept. Check: http://angeljohnsy.blogspot.com/2011/06/paint-application-using-bwlabel-concept.html

Code explanation:

    First create a figure with color buttons, axis and the pop-up menu for selecting the image.
 I am showing only .png(Portable Network Graphics) files in the pop-up menu.
directory=dir('*.png');

When the user selects the image file then the function ‘displayfile’ is called.





function paintapp
scz=get(0,'ScreenSize');
figure('Position',[round(scz(1,3)/4) round(scz(1,4)/8) 700 500],'MenuBar','None','NumberTitle','off','Name','Paint Application','Resize','off');
inputs=['RED   ';'GREEN ';'BLUE  ';'YELLOW';'BLACK ';'WHITE ';'ORANGE';'PURPLE';'BROWN ';'PINK  ';'GRAY  ';'LGREEN';'Save  ';'undo  '];
global top targetcolor replacecolor x y A color undocolor originalcolor point filename;
top=1;
targetcolor=[255 255 255];
xaxis=500;
yaxis=400;
for k=1:size(inputs,1)
uicontrol('Style','pushbutton','position',[xaxis yaxis 80 30],'String',inputs(k,:),'Callback',@paintme);
xaxis=xaxis+90;
if(mod(k,2)==0)
    yaxis=yaxis-50;
    xaxis=500;
end
end
ax=axes('Position',[0 0 .7 1],'xtick',[],'ytick',[]);
directory=dir('*.png');
files={directory.name}';
uicontrol('Style','popupmenu','position',[500 450 160 30],'Value',1,'String',files,'Callback',@displayfile);


The file is obtained from the string array ‘files’ and the image is displayed.

function displayfile(obj,~)
        ptr=get(obj,'value');
        filename=char(files(ptr));
        A=imread(filename);
        image(A);
    end
    

When the user clicks the color button the function ‘paintme’ is called.
Here, targetcolor is the color value at the point where the user clicks.


The replacecolor is the color the user selects from the colors displayed.


Based on the color selected the color value to be filled in the area is stored in ‘replacecolor’. If the user selects the undo button the color to be replaced will the replacecolor and the target color will be filled at the place.
                                                                 

                                                                                                                      






function paintme(object,~)
   color=get(object,'String');
   if(~isempty(A))
   switch(color(1,:))
       case 'RED   '
           while(strcmp(color,'RED   ')==1)
           replacecolor=[254 1 1];
            getpoints;
           end
       case 'GREEN '
           while(strcmp(color,'GREEN ')==1)
           replacecolor=[1 60 21];
          getpoints;
           end
       case 'BLUE  '
           while(strcmp(color,'BLUE  ')==1)
               replacecolor=[20 120 120];
           %replacecolor=[1 1 254];
            getpoints;
           end
       case 'YELLOW'
           while(strcmp(color,'YELLOW')==1)
           replacecolor=[240 240 1];
           getpoints;
           end
       case 'BLACK '
           while(strcmp(color,'BLACK ')==1)
           replacecolor=[1 1 1];
            getpoints;
           end
       case 'WHITE '
           while(strcmp(color,'WHITE ')==1)
           replacecolor=[254 254 254];
            getpoints;
           end
       case 'ORANGE'
          while(strcmp(color,'ORANGE')==1)
          replacecolor=[250 90 1];
         getpoints;
          end
       case 'PURPLE'
           while(strcmp(color,'PURPLE')==1)
           replacecolor=[90 20 60];
            getpoints;
           end
       case 'BROWN '
           replacecolor=[90 20 10];
           while(strcmp(color,'BROWN ')==1)
            getpoints;
           end
       case 'PINK  '
           while(strcmp(color,'PINK  ')==1)
           replacecolor=[220 90 90];
            getpoints;
           end
          
            case 'LGREEN'
           while(strcmp(color,'LGREEN')==1)
            replacecolor=[20 240 10];
            getpoints;
           end
       case 'GRAY  '
      
           while(strcmp(color,'GRAY  ')==1)
           replacecolor=[20 20 20];
            getpoints;
           end
          
        case 'undo  '
                floodfill(point(1),point(2),undocolor,originalcolor);
       case 'Save  '
           fname=strcat('my',filename);
           msg=strcat('File name:',fname);
           msgbox(msg,'FILE SAVED');
          
   end
   end
   
end

 If the user clicks the save button the file is saved.




The user should click on the image to fill with the replace color.
The ‘waitforbuttonpress’ function is used to get the user input graphically by a mouse click.
When user clicks a particular point, the x and y co-ordinate value is obtained using ‘get(ax,'CurrentPoint')’.
   
function getpoints
      
     try
         waitforbuttonpress;
         f=get(ax,'CurrentPoint');
         x=round(f(1,2));
         y=round(f(1,1));
        
         % check whether x and y is less than the size of the image
         targetcolor(1)=A(x,y,1);
         targetcolor(2)=A(x,y,2);
         targetcolor(3)=A(x,y,3);
        
         point(1)=x;
         point(2)=y;
         undocolor=replacecolor;
         originalcolor=targetcolor;
         floodfill(x,y,targetcolor,replacecolor);
        % end
    
     catch
         color='null';
     end
        
       
    end
    
Floodfill or bucketfill algorithm is used to fill the image portion.

function floodfill(x,y,targetcolor,replacecolor)
    top=1;
    queue=zeros(1);
   
    if((A(x,y,1)==targetcolor(1))&&(A(x,y,2)==targetcolor(2))&&(A(x,y,3)==targetcolor(3)))
        queue(top,1)=x;
        queue(top,2)=y;
        top=top+1;
        i=1;
     while(i~=top)
          l= queue(i,1);
          m=queue(i,2);
        
             
         if((A(l,m,1)==targetcolor(1))&&(A(l,m,2)==targetcolor(2))&&(A(l,m,3)==targetcolor(3)))
            
             w=m;
             e=m;
             wnode=1;
             enode=1;
             while((A(l,w,1)==targetcolor(1))&&(A(l,w,2)==targetcolor(2))&&(A(l,w,3)==targetcolor(3)))
                 wnode=wnode+1;
                 w=w-1;
             end
             while((A(l,e,1)==targetcolor(1))&&(A(l,e,2)==targetcolor(2))&&(A(l,e,3)==targetcolor(3)))
                 enode=enode+1;
                 e=e+1;
             end
             w=m+1;
             e=m-1;
             for j=1:wnode-1
                 A(l,w-j,1)=replacecolor(1);
                 A(l,w-j,2)=replacecolor(2);
                A(l,w-j,3)=replacecolor(3);
             end
             
             for j=1:enode-1
                A(l,e+j,1)=replacecolor(1);
                A(l,e+j,2)=replacecolor(2);
                A(l,e+j,3)=replacecolor(3);
             end
             snode=m-wnode+2;
             for j=snode:(snode+enode+wnode-4)
                if((A(l+1,j,1)==targetcolor(1))&&(A(l+1,j,2)==targetcolor(2))&&(A(l+1,j,3)==targetcolor(3)))
                   queue(top,1)=l+1;
                   queue(top,2)=j;
                   top=top+1;
               end
                if((A(l-1,j,1)==targetcolor(1))&&(A(l-1,j,2)==targetcolor(2))&&(A(l-1,j,3)==targetcolor(3)))
               queue(top,1)=l-1;
               queue(top,2)=j;
               top=top+1;
                end
                end
        
         end
        i=i+1;
    end
    end
    image(A);
end
end


References:
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GET FREE IMAGES AT:http://www.clker.com/





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3 comments:

thilinamees said... Reply to comment

Hi,
Thank you very much for putting your link in there :), I also wanted to write a Paint application in Java or MATLAB from long time back and I think your algorithm will be help me a lot in there. Thank you very much for sharing your knowledge. It will be much useful if you can extend your application to have the draw option as well. (by using or modifying getpts() in MATLAB or using mouse events in JAVA)

Rajesh K said... Reply to comment

I got this Error during Paint application matlab code.... how to rectify it....
Warning: popupmenu control requires a non-empty String
Control will not be rendered until all of its parameter values are valid

Please send solution to my e-mail: krajeshk1980.gm@gmail.com

Aaron Angel said... Reply to comment

@Rajesh K

Check whether there is png files in your working directory or you can change the below line in the code:

directory=dir('*.png');

Instead of 'png' , specify the file type you have in your working directory.

However, I suggest you to have a look at
http://angeljohnsy.blogspot.com/2011/06/paint-application-using-bwlabel-concept.html

which is quite faster than this method.

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