Page flip effect


(james koh) #1

i want to make my materials to have page flip effect and i got these javascript for this effect.
how do i change this script to actually work?
// Dimensions of the whole book
var BOOK_WIDTH = 630;
var BOOK_HEIGHT = 260;

// Dimensions of one page in the book
var PAGE_WIDTH = 300;
var PAGE_HEIGHT = 250;

// Vertical spacing between the top edge of the book and the papers
var PAGE_Y = (BOOK_HEIGHT - PAGE_HEIGHT) / 2;

// The canvas size equals to the book dimensions + this padding
var CANVAS_PADDING = 30;

var progress = 1;
var target = -1;

var canvas = document.getElementById(“pageflip-canvas”);
var context = canvas.getContext(“2d”);
var fillElt = document.getElementById(“fill”);
var droppedShadowElt = document.getElementById(“droppedShadow”);
var sharpShadowElt = document.getElementById(“sharpShadow”);
var progressElt = document.getElementById(“progress”);
var foldWidthElt = document.getElementById(“foldWidth”);
var foldXElt = document.getElementById(“foldX”);

// Resize the canvas to match the book size
canvas.width = BOOK_WIDTH;
canvas.height = BOOK_HEIGHT + (CANVAS_PADDING * 2);

progressElt.addEventListener(“change”, render, false);

function render() {

// Reset all pixels in the canvas
context.clearRect(0, 0, canvas.width, canvas.height);

// Ease progress towards the target value 
progress = progressElt.value;
// Strength of the fold is strongest in the middle of the book
var strength = 1 - Math.abs(progress);

// Width of the folded paper
var foldWidth = (PAGE_WIDTH * 0.5) * (1 - progress);

// X position of the folded paper
var foldX = PAGE_WIDTH * progress + foldWidth;

// How far the page should outdent vertically due to perspective
var verticalOutdent = 20 * strength;

foldWidthElt.value = foldWidth;
foldXElt.value = foldX;

context.save();
context.translate((BOOK_WIDTH / 2), PAGE_Y + CANVAS_PADDING);

drawFoldedPaper(foldX, foldWidth, verticalOutdent, fillElt.checked);


if (sharpShadowElt.checked) {
    drawSharpShadow(foldX, foldWidth, verticalOutdent, strength);
}

if (droppedShadowElt.checked) {
    drawDroppedShadow(foldX, foldWidth, strength);
}

context.restore();

}

// Draw the folded piece of paper
function drawFoldedPaper(foldX, foldWidth, verticalOutdent, fill) {
context.beginPath();
context.moveTo(foldX, 0);
context.lineTo(foldX, PAGE_HEIGHT);
context.quadraticCurveTo(foldX, PAGE_HEIGHT + (verticalOutdent * 2), foldX - foldWidth, PAGE_HEIGHT + verticalOutdent);
context.lineTo(foldX - foldWidth, -verticalOutdent);
context.quadraticCurveTo(foldX, -verticalOutdent * 2, foldX, 0);

if (fill) {
    // Gradient applied to the folded paper (highlights & shadows)
    var paperShadowWidth = (PAGE_WIDTH * 0.5) * Math.max(Math.min(1 - progress, 0.5), 0);
    var foldGradient = context.createLinearGradient(foldX - paperShadowWidth, 0, foldX, 0);
    foldGradient.addColorStop(0.35, '#fafafa');
    foldGradient.addColorStop(0.73, '#eeeeee');
    foldGradient.addColorStop(0.9, '#fafafa');
    foldGradient.addColorStop(1.0, '#e2e2e2');
    context.fillStyle = foldGradient;
    context.fill();
}
context.strokeStyle = 'rgba(0,0,0,0.06)';
context.lineWidth = 2;
context.stroke();

}

// Draw a sharp shadow on the left side of the page
function drawSharpShadow(foldX, foldWidth, verticalOutdent, strength) {
context.strokeStyle = ‘rgba(0,0,0,’+(0.05 * strength)+’)’;
context.lineWidth = 30 * strength;
context.beginPath();
context.moveTo(foldX - foldWidth, -verticalOutdent * 0.5);
context.lineTo(foldX - foldWidth, PAGE_HEIGHT + (verticalOutdent * 0.5));
context.stroke();
}

function drawDroppedShadow(foldX, foldWidth, strength) {
// Right side drop shadow
var rightShadowWidth = (PAGE_WIDTH * 0.5) * Math.max(Math.min(strength, 0.5), 0);
var rightShadowGradient = context.createLinearGradient(foldX, 0, foldX + rightShadowWidth, 0);
rightShadowGradient.addColorStop(0, ‘rgba(0,0,0,’+(strength*0.2)+’)’);
rightShadowGradient.addColorStop(0.8, ‘rgba(0,0,0,0.0)’);

context.fillStyle = rightShadowGradient;
context.beginPath();
context.moveTo(foldX, 0);
context.lineTo(foldX + rightShadowWidth, 0);
context.lineTo(foldX + rightShadowWidth, PAGE_HEIGHT);
context.lineTo(foldX, PAGE_HEIGHT);
context.fill();


// Left side drop shadow
var leftShadowWidth = (PAGE_WIDTH * 0.5) * Math.max(Math.min(strength, 0.5), 0);
var leftShadowGradient = context.createLinearGradient(foldX - foldWidth - leftShadowWidth, 0, foldX - foldWidth, 0);
leftShadowGradient.addColorStop(0, 'rgba(0,0,0,0.0)');
leftShadowGradient.addColorStop(1, 'rgba(0,0,0,'+(strength*0.15)+')');

context.fillStyle = leftShadowGradient;
context.beginPath();
context.moveTo(foldX - foldWidth - leftShadowWidth, 0);
context.lineTo(foldX - foldWidth, 0);
context.lineTo(foldX - foldWidth, PAGE_HEIGHT);
context.lineTo(foldX - foldWidth - leftShadowWidth, PAGE_HEIGHT);
context.fill();    

}


(Nick ) #2

Or let Hype animate the flip
You can customize your art to imitate a curled page as well.
And then use the Rotation Angle Y
make sure to move your centerpoint on your page illustration to the seam of the book.

pageflip.hype.zip (570.8 KB)


(james koh) #3

@nick Thank you. I checked your work. great idea. it really helped.


#4

Since Hype scenes cannot be separated into discrete ‘Divs’ which are pre-rendered, this technique probably won’t work without a lot of modification unfortunately. If you could separate each page into a Hype export, this might work. Can you share where you downloaded this code?


(james koh) #5

thank you Daniel for the reply. i downloaded this code here http://www.turnjs.com
and If this kind of effect is included to transitions. it would be perfect.
hope to get some more answers~ thank you again.