How to add on-screen virtual keyboard to a HTML5/Javascript/Canvas mobile game?

Question

I'm using HTML5 and canvas to design a game for which I need a keyboard input element. I do NOT want to use the device's keyboard, but instead, would like to make a custom keyboard that will be "fixed" to the screen/canvas for the duration of gameplay. I've seen NETTUT's sample of a CSS/JS/HTML5 keyboard. I would love to recreate the IOS-like interface in that example. However, I'm interested in a keyboard that is integrated into the canvas (in other words, no CSS). Is that possible? If so, what are the different methods that I use in order to draw the keyboard and give it functionality WITHIN the canvas using javascript? Scaling is also a concern. I'm extremely comfortable with HTML5/CSS but I am brand new to Javascript, so PLEASE break it ALL the way down. Thanks!

Answer 1

I do this in my library project (visual-js game engine) please this post Virtual keyboar in canvas2d .

Live example : hosted on jsfiddle

Problem for can be implementation (it is not pure and native to make easy copy paste) . In v-js ge you can draw custom canvas2d code. I will suggest you to look at :

keyboard.js

Here is idea. Create object with (x,y,w,h) and create in click event calculating method 'is it clicked in object bounds' . Best way is to put it all(obj's) in array then in click event check for whose obj's reseive clicks.

for example draws for that object can be :

if (obj.visible == true) {
 ctx.fillRect( obj.x , obj.y , obj.w , obj.h )
 ctx.fillText( obj.TEXT ,  obj.x -obj.w/2 , obj.y  ) // dont use height for ipad/iphone
 //  set up middle positon of text 
}

You can use samo model object for keyboard elements and also textbox element in canvas .( i dont talk about html tags )

In your game something action is done and you will need to create for every character uniq object with one char ( "A" , "SHIFT", "ENTER" etc ... ) make position for every obj. Draw all keyboard obj's .

' Now you need some flag to know what is current ACTIVE_ELEMENT (any param in your game).

There is one big problem in moment when you append char (some special chars) they have some text format deforms. I ask but there is no answer (i will post that question later) .

In this code block is solution for that problem (i cant simple pass value for current keycode) Looks like hardcode but it is only solution for me :

ROOT.CAPTURE_CHAR = "";
ROOT.CLEAR_CAPTURE_ON_PRESS_ENTER = true;
ROOT.LAST_CAPTURE_CHAR = "";
ROOT.ENTER_PRESSED = false;
ROOT.SHIFT_PRESSED = false;
ROOT.ACTION_ON_KEY_DOWN = function(){};

...

//@@@@@@@@@@@@@@@@@@@@@@@@@@
//@@@@@@@@@@@@@@@@@@@@@@@@@@
// SPECIAL FOR TEXTBOX
//@@@@@@@@@@@@@@@@@@@@@@@@@@
//@@@@@@@@@@@@@@@@@@@@@@@@@@
SYS.DEBUG.LOG("KEYBOARD-->> Show users types : " + e.keyCode );         
var keynum;
if(window.event){ keynum = e.keyCode;}else{if(e.which){ keynum = e.which;}}
//console.log(String.fromCharCode(keynum));

if (e.keyCode == 16){
ROOT.SHIFT_PRESSED = true;
}

if (e.keyCode == 8) {
SYS.DEBUG.LOG("textbox delete last char!");         
ROOT.CAPTURE_CHAR = remove_last( ROOT.CAPTURE_CHAR );

}
else if(e.keyCode == 13){
ROOT.ENTER_PRESSED = true;
}
else {

if (ROOT.SHIFT_PRESSED == false) {

   if (e.keyCode == 189) {
    ROOT.CAPTURE_CHAR+="_";
    ROOT.LAST_CAPTURE_CHAR ="_";
  }
  else if (e.keyCode == 187) {
    ROOT.CAPTURE_CHAR+="+";
    ROOT.LAST_CAPTURE_CHAR ="+";
  }
  else if (e.keyCode == 187) {
    ROOT.CAPTURE_CHAR+="+";
    ROOT.LAST_CAPTURE_CHAR ="+";
  }
  else if (e.keyCode == 188) {
    ROOT.CAPTURE_CHAR+=",";
    ROOT.LAST_CAPTURE_CHAR =",";
  }
  else if (e.keyCode == 190) {
    ROOT.CAPTURE_CHAR+=".";
    ROOT.LAST_CAPTURE_CHAR =".";
  }
  else if (e.keyCode == 191) {
    ROOT.CAPTURE_CHAR+="/";
    ROOT.LAST_CAPTURE_CHAR ="/";
  }
  else if (e.keyCode == 186) {
    ROOT.CAPTURE_CHAR+=";";
    ROOT.LAST_CAPTURE_CHAR =";";
  }
  else if (e.keyCode == 222) {
    ROOT.CAPTURE_CHAR+="'";
    ROOT.LAST_CAPTURE_CHAR ="'";
  }
  else if (e.keyCode == 220) {
    ROOT.CAPTURE_CHAR+= "\\";
    ROOT.LAST_CAPTURE_CHAR ='\\';
  }
  else if (e.keyCode == 219) {
    ROOT.CAPTURE_CHAR+='[';
    ROOT.LAST_CAPTURE_CHAR ='[';
  }
  else if (e.keyCode == 221) {
    ROOT.CAPTURE_CHAR+=']';
    ROOT.LAST_CAPTURE_CHAR =']';
  }
  else{

    ROOT.CAPTURE_CHAR+=(String.fromCharCode(keynum).toLowerCase());
    ROOT.LAST_CAPTURE_CHAR = (String.fromCharCode(keynum).toLowerCase());

  }


}
else {

  if (e.keyCode == 50) {
    ROOT.CAPTURE_CHAR+="@";
    ROOT.LAST_CAPTURE_CHAR ="@";
  }
  else if (e.keyCode == 49) {
    ROOT.CAPTURE_CHAR+="!";
    ROOT.LAST_CAPTURE_CHAR ="!";
  }
  else if (e.keyCode == 51) {
    ROOT.CAPTURE_CHAR+="#";
    ROOT.LAST_CAPTURE_CHAR ="#";
  }
  else if (e.keyCode == 52) {
    ROOT.CAPTURE_CHAR+="$";
    ROOT.LAST_CAPTURE_CHAR ="$";
  }
  else if (e.keyCode == 53) {
    ROOT.CAPTURE_CHAR+="%";
    ROOT.LAST_CAPTURE_CHAR ="%";
  }
  else if (e.keyCode == 54) {
    ROOT.CAPTURE_CHAR+="^";
    ROOT.LAST_CAPTURE_CHAR ="^";
  }
  else if (e.keyCode == 55) {
    ROOT.CAPTURE_CHAR+="&";
    ROOT.LAST_CAPTURE_CHAR ="&";
  }
  else if (e.keyCode == 56) {
    ROOT.CAPTURE_CHAR+="*";
    ROOT.LAST_CAPTURE_CHAR ="*";
  }
  else if (e.keyCode == 57) {
    ROOT.CAPTURE_CHAR+="(";
    ROOT.LAST_CAPTURE_CHAR ="(";
  }
  else if (e.keyCode == 48) {
    ROOT.CAPTURE_CHAR+=")";
    ROOT.LAST_CAPTURE_CHAR =")";
  }
  else if (e.keyCode == 189) {
    ROOT.CAPTURE_CHAR+="_";
    ROOT.LAST_CAPTURE_CHAR ="_";
  }
  else if (e.keyCode == 187) {
    ROOT.CAPTURE_CHAR+="+";
    ROOT.LAST_CAPTURE_CHAR ="+";
  }
  else if (e.keyCode == 187) {
    ROOT.CAPTURE_CHAR+="+";
    ROOT.LAST_CAPTURE_CHAR ="+";
  }
  else if (e.keyCode == 188) {
    ROOT.CAPTURE_CHAR+="<";
    ROOT.LAST_CAPTURE_CHAR ="<";
  }
  else if (e.keyCode == 190) {
    ROOT.CAPTURE_CHAR+=">";
    ROOT.LAST_CAPTURE_CHAR =">";
  }
  else if (e.keyCode == 191) {
    ROOT.CAPTURE_CHAR+="?";
    ROOT.LAST_CAPTURE_CHAR ="?";
  }
  else if (e.keyCode == 186) {
    ROOT.CAPTURE_CHAR+=":";
    ROOT.LAST_CAPTURE_CHAR =":";
  }
  else if (e.keyCode == 222) {
    ROOT.CAPTURE_CHAR+='"';
    ROOT.LAST_CAPTURE_CHAR ='"';
  }
  else if (e.keyCode == 220) {
    ROOT.CAPTURE_CHAR+='|';
    ROOT.LAST_CAPTURE_CHAR ='|';
  }
  else if (e.keyCode == 219) {
    ROOT.CAPTURE_CHAR+='{';
    ROOT.LAST_CAPTURE_CHAR ='{';
  }
  else if (e.keyCode == 221) {
    ROOT.CAPTURE_CHAR+='}';
    ROOT.LAST_CAPTURE_CHAR ='}';
  }




  else {

    ROOT.CAPTURE_CHAR+=(String.fromCharCode(keynum).toUpperCase());
    ROOT.LAST_CAPTURE_CHAR = (String.fromCharCode(keynum).toUpperCase());

  }

}

}


ROOT.ACTION_ON_KEY_DOWN();


//@@@@@@@@@@@@@@@@@@@@@@@@@



if (typeof ROOT.TARGET_MODUL != 'undefined' && typeof ROOT.TARGET != 'undefined' ) {

      ROOT.CAPTURE_CHAR = ROOT.CAPTURE_CHAR.replace(/[^\x00-\x7F]/g, "");
      ROOT.CAPTURE_CHAR = ROOT.CAPTURE_CHAR.replace(/[^A-Za-z 0-9 \.,\?""!#\$%\^&\*\(\)-_=\+;:<>\/\\\|\}\{\[\]`~]*/g, '');

   window[ROOT.PROGRAM_NAME].ENGINE.MODULES.ACCESS(ROOT.TARGET_MODUL).GAME_OBJECTS.ACCESS(ROOT.TARGET).TEXTBOX.TEXT = ROOT.CAPTURE_CHAR;
    if (ROOT.ENTER_PRESSED == true) {

        window[ROOT.PROGRAM_NAME].ENGINE.MODULES.ACCESS(ROOT.TARGET_MODUL).GAME_OBJECTS.ACCESS(ROOT.TARGET).TEXTBOX.ON_PRESS_ENTER();

         if ( ROOT.CLEAR_CAPTURE_ON_PRESS_ENTER == true ) 
         {

             ROOT.CAPTURE_CHAR = '';

         }
    }
}
ROOT.ENTER_PRESSED = false;
//local_go.TEXTBOX.TEXT =  ROOT_EVENTS.ROOT_ENGINE.KEYBOARD.CAPTURE_CHAR;
//@@@@@@@@@@@@@@@@@@@@@@@@@@
//@@@@@@@@@@@@@@@@@@@@@@@@@@