我有这个自定义控件：
UIImageView我在这里继承了它：
<!DOCTYPE html>
<html>
<head>
<title>Login</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link type="text/css" rel="stylesheet" href="/demo/css/bootstrap.css" />
<link type="text/css" rel="stylesheet" href="css/bootstrap-responsive.css" />
<script type="text/javascript" src="js/jquery.min.js"></script>
<script type="text/javascript" src="js/bootstrap.min.js"></script>
<link href='http://fonts.googleapis.com/css?family=Lato:100,300,400,700' rel='stylesheet' type='text/css'>
<style >
*{
margin:0 !important;
padding:0 ! important;
}
body {
width: 100%;
min-height: 800px;
background-size: 100%;
background-repeat: no-repeat;
position:absolute;
background-image: url(demo_BG_1024.png);
background-color: rgb(0,0,0);
}
ul{
padding-top: 0px;
}
.form-signin {
width:500px !important;
height:300px ! important;
}
.form-signin {
max-width: 500px;
padding: 19px 29px 29px;
margin: 0 auto 20px;
background-color: #fff;
border: 1px solid #e5e5e5;
-webkit-border-radius: 5px;
-moz-border-radius: 5px;
border-radius: 5px;
-webkit-box-shadow: 0 1px 2px rgba(0,0,0,.05);
-moz-box-shadow: 0 1px 2px rgba(0,0,0,.05);
box-shadow: 0 1px 2px rgba(0,0,0,.05);
}
.form-signin .form-signin-heading,
.form-signin .checkbox {
margin-bottom: 10px;
}
.form-signin input[type="text"],
.form-signin input[type="password"] {
font-size: 16px;
height: auto;
margin-bottom: 15px;
padding: 7px 9px;
}
.left {
float: left;
display: block;
width: 25%;
padding-left: 0px;
text-align: left;
}
.right {
float: right;
display: block;
width: 75%;
text-align: right;
padding-right: 0px;
}
.header
{
font-family: 'Lato', sans-serif;
font-weight: 700;
color: white;
font-size: 64px;
padding-top: 60px;
}
.header2
{
padding-top: 0px;
font-family: 'Lato', sans-serif;
font-weight: 300;
color: white;
font-size: 46px;
}
.header3
{
padding-top: 0px;
font-family: 'Lato', sans-serif;
font-weight: 300;
color: white;
font-size: 30px;
}
.header4
{
padding-top: 0px;
font-family: 'Lato', sans-serif;
font-weight: 300;
color: white;
font-size: 18px;
}
nav{
position: fixed;
right: 0;
left: 0;
z-index: 1030;
margin-bottom: 0;
width: 100%;
height: 78px;
padding:0 px;
background-color: rgb(0,0,0);
}
ul li {
list-style-type: none;
margin: 0px;
display: inline-block;
}
#logo_image
{
padding: 10px 30px!important;
}
.menu_buttons
{
font-family:'Lato', sans-serif;
font-weight: 400;
font-size: 18px;
color:white ;
display: inline-block;
padding: 10px 30px !important;
}
.demobtn {
height:1.3em;
width:2.5em;
background-color:#00b6ee;
display:inline-block;
cursor:pointer;
color:#ffffff;
font-family:'Lato', sans-serif;
font-weight: 300;
font-size:30px;
padding:10px 100px;
text-decoration:none;
text-shadow:0px 0px 0px #2f6627;
}
.demobtn:hover {
`enter code here`background-color:#00b6ee;
text-decoration:none;
}
.demobtn:active {
position:relative;
text-decoration:none;
top:1px;
}
.inputfield
{
position:relative;
top:30px;
font-size: 60px!important;
font-family:'Lato', sans-serif !important;
font-weight: 400;
color:white ;
width:400px;
line-height: 100px!important;
opacity:0.2;
}
.overrideheight {
height: 90px;
}
.sign-in
{
padding-top: 100px;
margin-top:100px;
}
.myForm
{
position:relative;
top:230px;
margin-left: auto;
margin-right: auto;
}
</style>
</head>
<body>
<div class="row">
<nav>
<ul class="left" ><li id="logo_image"><img alt="logo" src="img/demo_logo.png"></li></ul>
<ul class="right" >
<li><a class="menu_buttons" href="#">Login</a></li>
</ul>
</nav>
</div>
<div class="row ">
<div class="myForm">
<div class="row sign-in ">
<div class="col-xs-6 col-md-4 col-lg-4"></div>
<div class="col-xs-6 col-md-4 col-lg-4 text-center"><h2 class="header2">Login to demo</h2></div>
<div class="col-xs-6 col-md-4 col-lg-4"></div>
</div>
<br>
</div>
</div>
<form class="text-center form-group" action="" method="post">
<div class="row">
<input type="text" id="username" name="name" class="form-control overrideheight" placeholder="Username"><br><br>
</div>
<input id="password" type="password" name="password" class="form-control overrideheight" placeholder="Password"><br><br>
<br>
<input type="submit" id="submit" value="Login" /><br>
</form>
<div class="navbar-fixed-bottom">
<ul class="left">
<li><a href="#" class="menu_buttons" >Home</a></li>
<li><a href="#" class="menu_buttons" >About</a></li>
<li><a href="#" class="menu_buttons" >Support</a></li>
</ul>
<ul class="right">
<li><a href="#" class="menu_buttons" >Powered by Demo</a></li>
</ul>
</div>
<script>
$(document).ready(function(){
$("#submit").attr("disabled",true);
var username = '';
$("#username").on('change keyup paste mouseup', function() {
if ($(this).val() != username) {
username = $(this).val();
}
});
var password = '';
$("#username").on('change keyup paste mouseup', function() {
if ($(this).val() != password) {
password = $(this).val();
if(username!=""&&password!="")
{
$("#submit").attr("disabled",false);
}
}
});
});
</script>
</body>
</html>
和行动：
public class DrawingArea : Panel
{
public DrawingArea()
{
SetStyle(ControlStyles.UserPaint |ControlStyles.DoubleBuffer, true);
}
/// <summary>
/// Override this method in subclasses for drawing purposes.
/// </summary>
protected virtual void OnDraw(Graphics graphics)
{
}
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Security", "CA2122:DoNotIndirectlyExposeMethodsWithLinkDemands")]
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
protected override CreateParams CreateParams
{
get
{
CreateParams cp = base.CreateParams;
cp.ExStyle |= 0x00000020; //WS_EX_TRANSPARENT
return cp;
}
}
protected override void OnPaintBackground(PaintEventArgs pevent)
{
// Don't paint background
}
protected override void OnPaint(PaintEventArgs e)
{
// Update the private member so we can use it in the OnDraw method
Graphics graphics = e.Graphics;
// Set the best settings possible (quality-wise)
graphics.TextRenderingHint =
System.Drawing.Text.TextRenderingHint.AntiAlias;
graphics.InterpolationMode =
System.Drawing.Drawing2D.InterpolationMode.HighQualityBilinear;
graphics.PixelOffsetMode =
System.Drawing.Drawing2D.PixelOffsetMode.HighQuality;
graphics.SmoothingMode =
System.Drawing.Drawing2D.SmoothingMode.HighQuality;
// Calls the OnDraw subclass method
OnDraw(graphics);
}
}
基本上我要做的是捕捉屏幕，然后在其上添加黑色透明屏幕，这样我就可以用它来裁剪图片。