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var KEY = { RIGHT:39, UP:38, LEFT:37, DOWN:40 };
var sa2d = {
descript : ""
, canvas : null
, context : null
, init : function(canvas_id) {
sa2d.canvas = document.getElementById(canvas_id);
sa2d.context = sa2d.canvas.getContext("2d");
}
, line_to : function(x1, y1, x2, y2) {
var context = sa2d.context;
context.beginPath();
context.moveTo(x1, y1);
context.lineTo(x2, y2);
context.stroke();
context.closePath();
}
, clearRect : function(x, y, width, height) {
var context = sa2d.context;
context.clearRect(x, y, width, height);
}
, draw_circle : function(x, y, radius, start_angle, end_angle, anticlockwise) {
var context = sa2d.context;
context.beginPath();
context.arc(x, y, radius, start_angle, end_angle, anticlockwise);
context.stroke(); //context.fill();
context.closePath();
}
// https://developer.mozilla.org/en/Canvas_tutorial/Using_images
, draw_image : function(image_url, x, y, width, height) {
var context = sa2d.context;
var img = new Image();
img.onload = function() {
context.drawImage(img, x, y, width, height);
};
img.src = image_url;
}
};
var handler = {
descript : ""
, init : function() {
if(sa2d.context === null) {
sa2d.init("lesson1-canvas");
}
}
, line_to_test : function() {
var form = document.getElementsByName("interface_form")[0];
var x1 = form.line_x1.value;
var y1 = form.line_y1.value;
var x2 = form.line_x2.value;
var y2 = form.line_y2.value;
sa2d.line_to(x1, y1, x2, y2);
}
, draw_circle_test : function() {
var form = document.getElementsByName("interface_form")[0];
var x = form.circle_x.value;
var y = form.circle_y.value;
var radius = form.circle_radius.value;
var start_angle = form.circle_start_angle.value;
var end_angle = (Math.PI * 2) / form.circle_end_angle.value;
var anticlockwise = true;
sa2d.draw_circle(x, y, radius, start_angle, end_angle, anticlockwise);
}
, draw_image_test : function() {
var form = document.getElementsByName("interface_form")[0];
var x = form.image_x.value;
var y = form.image_y.value;
var width = form.image_width.value;
var height = form.image_height.value;
sa2d.draw_image("images/pororo.jpg", x, y, width, height);
}
, clear_rect_test : function() {
var form = document.getElementsByName("interface_form")[0];
var x = form.image_x.value;
var y = form.image_y.value;
var width = form.image_width.value;
var height = form.image_height.value;
sa2d.clearRect(x, y, width, height);
}
, keyHandler : function(event) {
var code = event.keyCode;
switch(code) {
case KEY.UP:
sa2d.clearRect(0, 0, 10000, 10000);
var form = document.getElementsByName("interface_form")[0];
form.image_y.value = parseInt(form.image_y.value) - 10;
handler.draw_image_test();
break;
case KEY.DOWN:
sa2d.clearRect(0, 0, 10000, 10000);
var form = document.getElementsByName("interface_form")[0];
form.image_y.value = parseInt(form.image_y.value) + 10;
handler.draw_image_test();
break;
case KEY.LEFT:
sa2d.clearRect(0, 0, 10000, 10000);
var form = document.getElementsByName("interface_form")[0];
form.image_x.value = parseInt(form.image_x.value) - 10;
handler.draw_image_test();
break;
case KEY.RIGHT:
sa2d.clearRect(0, 0, 10000, 10000);
var form = document.getElementsByName("interface_form")[0];
form.image_x.value = parseInt(form.image_x.value) + 10;
handler.draw_image_test();
break;
}
}
, test : function() {
}
}; |
