1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
|
<div class="editor">
<canvas id="canvas" style="background:#fff; border:1px inset #888" width="400" height="200"></canvas><br>
<button type="button" id="blackbtn" style="background-color: black; width: 4em; height: 2em"></button> <button type="button" id="whitebtn" style="background-color: white; width: 4em; height: 2em"></button>
<button type="button" id="redbtn" style="background-color: red; width: 4em; height: 2em"></button> <button type="button" id="bluebtn" style="background-color: blue; width: 4em; height: 2em"></button><br>
<button type="button" id="magentabtn" style="background-color: magenta; width: 4em; height: 2em"></button> <button type="button" id="cyanbtn" style="background-color: cyan; width: 4em; height: 2em"></button>
<button type="button" id="yellowbtn" style="background-color: yellow; width: 4em; height: 2em"></button> <button type="button" id="greenbtn" style="background-color: lime; width: 4em; height: 2em"></button><br>
pen size : <input type="range" id="pensize-slider" value="1" min="1" max="99" style="vertical-align: middle;">
<input type="number" id="pensize" value="1" min="1" max="99" style="width: 50px;"><br>
<button type="button" id="undobtn">Undo</button> <button type="button" id="clearbtn">Clear</button><br>
<button type="button" id="sendbtn">Send</button>
</div>
<p style="max-width: 400px;margin: auto;margin-bottom: 20px;">Pro tip: it case it ain't obvious you can use white as an eraser<br>
Librewolf users have to enable canvas access before sending</p>
<footer><a href="/about.html">About this site</a></footer>
</main>
</body>
<script type="text/javascript">
const canvas = document.getElementById('canvas');
const ctx = canvas.getContext('2d');
ctx.getImageData(0, 0, 1, 1); // to trigger librewolf's protection (and allow users to enable canvas before publishing)
ctx.lineCap = "round";
ctx.lineJoin = "round";
//ctx.fillStyle = "black";
let isDrawing = false;
let undoStack = [];
let maxUndoSteps = 20; // Adjust as needed
function saveState() {
undoStack.push(ctx.getImageData(0, 0, canvas.width, canvas.height));
if (undoStack.length > maxUndoSteps) {
undoStack.shift();
}
}
function undo() {
if (undoStack.length > 0) {
const imageData = undoStack.pop();
ctx.putImageData(imageData, 0, 0);
}
}
function clear() {
saveState();
ctx.clearRect(0, 0, canvas.width, canvas.height);
}
function startDrawing(event) {
event.preventDefault();
saveState();
isDrawing = true;
draw(event);
}
function startDrawingTouch(event) {
event.preventDefault();
saveState();
isDrawing = true;
drawTouch(event);
}
function draw(event) {
event.preventDefault();
if (!isDrawing) return;
const x = event.clientX - canvas.offsetLeft + window.pageXOffset;
const y = event.clientY - canvas.offsetTop + window.pageYOffset;
ctx.lineTo(x, y);
ctx.stroke();
}
function drawTouch(event) {
event.preventDefault();
if (!isDrawing) return;
const x = event.touches[0].clientX - canvas.offsetLeft + window.pageXOffset;
const y = event.touches[0].clientY - canvas.offsetTop + window.pageYOffset;
ctx.lineTo(x, y);
ctx.stroke();
}
function stopDrawing() {
event.preventDefault();
isDrawing = false;
ctx.beginPath();
}
canvas.addEventListener("mousedown", startDrawing);
canvas.addEventListener("mousemove", draw);
canvas.addEventListener("mouseup", stopDrawing);
canvas.addEventListener("mouseout", stopDrawing);
canvas.addEventListener("touchstart", startDrawingTouch);
canvas.addEventListener("touchmove", drawTouch);
canvas.addEventListener("touchend", stopDrawing);
canvas.addEventListener("touchcancel", stopDrawing);
function sendPic() {
fetch("/api/post", {
method: "POST",
body: JSON.stringify({ {{ if .threadId }}
thread: "{{.threadId}}",{{ end }}
picture: canvas.toDataURL("image/png")
}),
headers: {
"Content-type": "application/json; charset=UTF-8"
}
})
.then((response) => response.json())
.then((json) => {
if (json.status == "ok") {
location.reload();
}
});
}
const sendbtn = document.getElementById('sendbtn');
sendbtn.addEventListener("click", sendPic);
const undobtn = document.getElementById('undobtn');
undobtn.addEventListener("click", undo);
const clearbtn = document.getElementById('clearbtn');
clearbtn.addEventListener("click", clear);
const blackbtn = document.getElementById('blackbtn');
blackbtn.addEventListener("click", () => {
ctx.strokeStyle="#000000";
});
const whitebtn = document.getElementById('whitebtn');
whitebtn.addEventListener("click", () => {
ctx.strokeStyle="#ffffff";
});
const redbtn = document.getElementById('redbtn');
redbtn.addEventListener("click", () => {
ctx.strokeStyle="#ff0000";
});
const bluebtn = document.getElementById('bluebtn');
bluebtn.addEventListener("click", () => {
ctx.strokeStyle="#0000ff";
});
const greenbtn = document.getElementById('greenbtn');
greenbtn.addEventListener("click", () => {
ctx.strokeStyle="#00ff00";
});
const magentabtn = document.getElementById('magentabtn');
magentabtn.addEventListener("click", () => {
ctx.strokeStyle="#ff00ff";
});
const cyanbtn = document.getElementById('cyanbtn');
cyanbtn.addEventListener("click", () => {
ctx.strokeStyle="#00ffff";
});
const yellowbtn = document.getElementById('yellowbtn');
yellowbtn.addEventListener("click", () => {
ctx.strokeStyle="#ffff00";
});
const pensize = document.getElementById('pensize');
pensize.addEventListener("change", () => {
ctx.lineWidth=pensize.value;
console.log(pensize.value)
});
pensize.addEventListener("input", () => {
pensizeSlider.value = pensize.value;
ctx.lineWidth = pensize.value;
});
const pensizeSlider = document.getElementById('pensize-slider');
pensizeSlider.addEventListener("input", () => {
pensize.value = pensizeSlider.value;
ctx.lineWidth = pensizeSlider.value;
});
// Keyboard shortcut for undo
document.addEventListener("keydown", function(event) {
if (event.ctrlKey && event.key === 'z') {
undo();
}
});
</script>
</html>
|
