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);

         color='null';

    

     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

SEE ALSO: Paint application using bwlabel concept

References:

Digital Image Processing Using MATLAB, 2nd ed.

http://en.wikipedia.org/wiki/Flood_fill

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