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ECA 225

ECA 225. Applied Online Programming. DHTML. resolution independence. commonly used resolutions 640 X 480 800 X 600 1024 X 768 to center content independent of resolution calculate dimensions of display window. ( window_width – stage_width ) / 2. resolution independence cont ….

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ECA 225

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  1. ECA 225 AppliedOnline Programming DHTML ECA 225 Applied Interactive Programming

  2. resolution independence • commonly used resolutions • 640 X 480 • 800 X 600 • 1024 X 768 • to center content independent of resolution • calculate dimensions of display window ( window_width – stage_width ) / 2 ECA 225 Applied Interactive Programming

  3. resolution independence cont … • think of objects on a canvas or stage with limited width and height • every object on the page will be offset from the L and T edges by a distance equal to the size of the margin around this imaginary stage • EG, if a display window is 760 X 560 and the stage is 620 X 300 border_width = ( 760 – 620 ) / 2 ECA 225 Applied Interactive Programming

  4. Display Window Offset 760 620 80 460 ( H – 300 ) / 2 300 Avalon Books ( W – 620 ) / 2 70 ECA 225 Applied Interactive Programming

  5. resolution independence cont … • once we find the available width and height of the browser window we can determine the amount of margin needed to center the content W = ( window_width – 620 ) / 2 H = ( window_height – 300 ) / 2 • after determining these values we can add them to the appropriate coordinates for each object on our page ECA 225 Applied Interactive Programming

  6. calculating size of display window • NS4 & W3C • width & height of display window, including menu, toolbars, status bar • window.outerWidth • window.outerHeight • width & height of available window only ( minus menu, toolbars, etc ) • window.innerWidth • window.innerHeight ECA 225 Applied Interactive Programming

  7. calculating size of display window • Internet Explorer headaches • no version of IE supports the W3C properties • IE4 & IE5 • size of web page body • document.body.clientWidth • document.body.clientHeight • IE6 • no longer supports document.body property • use document.documentElement property • document.documentElement.offsetWidth • document.documentElement.offsetHeight ECA 225 Applied Interactive Programming

  8. modify the API • add the following functions to the API to return size of document window • winWidth( ) • winHeight( ) • algorithm • if window.innerWidth and window.innerHeight are supported, return those values ( NS4 & W3C ) • otherwise, if the browser supports the document.documentElement object, return document.documentElement.offsetWidth and document.documentElement.offsetHeight ( IE6 ) • otherwise, if document.body.clientWidth and document.body.clientHeight are supported, return those values ( IE4 & IE5 ) ECA 225 Applied Interactive Programming

  9. winWidth( ) function winWidth( ){ if(window.innerWidth) return window.innerWidth; else if(document.documentElement) return document.documentElement.offsetWidth; else if(document.body.clientWidth) return document.body.clientWidth; } W = ( winWidth( ) – 620 ) / 2 ECA 225 Applied Interactive Programming

  10. winHeight( ) function winHeight( ){ if(window.innerHeight) return window.innerHeight; else if(document.documentElement) return document.documentElement.offsetHeight; else if(document.body.clientHeight) return document.body.clientHeight; } H = ( winHeight( ) – 300 ) / 2 ECA 225 Applied Interactive Programming

  11. modify the Web Page • add W and H to values passed in the placeObjects( ) function function placeObjects(){ placeIt("avalon",W+175,H+10); placeIt("books",W+175,H+10); placeIt("AB",W+230,H+40); placeIt("Fiction",W+5,H+5); placeIt("NFiction",W+475,H+5); moveAvalon(); // } ECA 225 Applied Interactive Programming

  12. modify the Web Page • add W and H to coordinates used to stop animation in move functions function moveAvalon(){ var y = yCoord("avalon"); if( y <= H+275 ){ shiftIt("avalon",0,4); shiftIt("books",0,4); setTimeout("moveAvalon()",20); } } function moveBooks(){ var x = xCoord("books"); if( x <= W+320 ){ shiftIt("books",4,0); setTimeout("moveBooks()",20); } } ECA 225 Applied Interactive Programming

  13. path animation • animation is not limited to straight line • sets of ( x, y ) coordinates stored in 2 arrays • calculate the number of pixels the object moves each time the move function is called • read the 2 arrays, one index at a time x = new Array(5,5,5,5,5,6,6,6,7,7,7,8,8,8,9,9,9,10,10,10);y = new Array(0,0,0,0,0,1,1,1,2,2,2,3,3,3,4,4,4,5,6,7); ECA 225 Applied Interactive Programming

  14. path animation • “object_name” is moved from point to point by the corresponding number of pixels stored in the two arrays x = new Array(5,5,5,5,5,6,6,6,7,7,7,8,8,8,9,9,9,10,10,10);y = new Array(0,0,0,0,0,1,1,1,2,2,2,3,3,3,4,4,4,5,6,7);index = 0; function moveObject( ){if( index <= x.length – 1 ){ shiftIt(“object_name”, x[index], y[index]; index++;} } ECA 225 Applied Interactive Programming

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