项目中对图片的缩放和水印效果
时间:2022-04-22
本文章向大家介绍项目中对图片的缩放和水印效果,主要内容包括其使用实例、应用技巧、基本知识点总结和需要注意事项,具有一定的参考价值,需要的朋友可以参考一下。
///<summary>
/// 获取一个图片按等比例缩小后的大小。
///</summary>
///<param name="maxWidth">需要缩小到的宽度</param>
///<param name="maxHeight">需要缩小到的高度</param>
///<param name="imageOriginalWidth">图片的原始宽度</param>
///<param name="imageOriginalHeight">图片的原始高度</param>
///<returns>返回图片按等比例缩小后的实际大小</returns>
public static Size GetNewSize(int maxWidth, int maxHeight, int imageOriginalWidth, int imageOriginalHeight)
{
double w = 0.0;
double h = 0.0;
double sw = Convert.ToDouble(imageOriginalWidth);
double sh = Convert.ToDouble(imageOriginalHeight);
double mw = Convert.ToDouble(maxWidth);
double mh = Convert.ToDouble(maxHeight);
if (sw < mw && sh < mh)
{
w = sw;
h = sh;
}
else if ((sw / sh) > (mw / mh))
{
w = maxWidth;
h = (w * sh) / sw;
}
else
{
h = maxHeight;
w = (h * sw) / sh;
}
return new Size(Convert.ToInt32(w), Convert.ToInt32(h));
}
///<summary>
/// 对给定的一个图片(Image对象)生成一个指定大小的缩略图。
///</summary>
///<param name="originalImage">原始图片</param>
///<param name="thumMaxWidth">缩略图的宽度</param>
///<param name="thumMaxHeight">缩略图的高度</param>
///<returns>返回缩略图的Image对象</returns>
public static System.Drawing.Image GetThumbNailImage(System.Drawing.Image originalImage, int thumMaxWidth, int thumMaxHeight)
{
Size thumRealSize = Size.Empty;
System.Drawing.Image newImage = originalImage;
Graphics graphics = null;
try
{
thumRealSize = GetNewSize(thumMaxWidth, thumMaxHeight, originalImage.Width, originalImage.Height);
newImage = new Bitmap(thumRealSize.Width, thumRealSize.Height);
graphics = Graphics.FromImage(newImage);
graphics.CompositingQuality = CompositingQuality.HighQuality;
graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
graphics.SmoothingMode = SmoothingMode.HighQuality;
graphics.Clear(Color.Transparent);
graphics.DrawImage(originalImage, new Rectangle(0, 0, thumRealSize.Width, thumRealSize.Height), new Rectangle(0, 0, originalImage.Width, originalImage.Height), GraphicsUnit.Pixel);
}
catch { }
finally
{
if (graphics != null)
{
graphics.Dispose();
graphics = null;
}
}
return newImage;
}
///<summary>
/// 对给定的一个图片文件生成一个指定大小的缩略图。
///</summary>
///<param name="originalImage">图片的物理文件地址</param>
///<param name="thumMaxWidth">缩略图的宽度</param>
///<param name="thumMaxHeight">缩略图的高度</param>
///<returns>返回缩略图的Image对象</returns>
public static System.Drawing.Image GetThumbNailImage(string imageFile, int thumMaxWidth, int thumMaxHeight)
{
System.Drawing.Image originalImage = null;
System.Drawing.Image newImage = null;
try
{
originalImage = System.Drawing.Image.FromFile(imageFile);
newImage = GetThumbNailImage(originalImage, thumMaxWidth, thumMaxHeight);
}
catch { }
finally
{
if (originalImage != null)
{
originalImage.Dispose();
originalImage = null;
}
}
return newImage;
}
///<summary>
/// 对给定的一个图片文件生成一个指定大小的缩略图,并将缩略图保存到指定位置。
///</summary>
///<param name="originalImageFile">图片的物理文件地址</param>
///<param name="thumbNailImageFile">缩略图的物理文件地址</param>
///<param name="thumMaxWidth">缩略图的宽度</param>
///<param name="thumMaxHeight">缩略图的高度</param>
public static void MakeThumbNail(string originalImageFile, string thumbNailImageFile, int thumMaxWidth, int thumMaxHeight)
{
System.Drawing.Image newImage = GetThumbNailImage(originalImageFile, thumMaxWidth, thumMaxHeight);
try
{
newImage.Save(thumbNailImageFile, ImageFormat.Jpeg);
}
catch
{ }
finally
{
newImage.Dispose();
newImage = null;
}
}
///<summary>
/// 将一个图片的内存流调整为指定大小,并返回调整后的内存流。
///</summary>
///<param name="originalImageStream">原始图片的内存流</param>
///<param name="newWidth">新图片的宽度</param>
///<param name="newHeight">新图片的高度</param>
///<returns>返回调整后的图片的内存流</returns>
public static MemoryStream ResizeImage(Stream originalImageStream, int newWidth, int newHeight)
{
MemoryStream newImageStream = null;
System.Drawing.Image newImage = GetThumbNailImage(System.Drawing.Image.FromStream(originalImageStream), newWidth, newHeight);
if (newImage != null)
{
newImageStream = new MemoryStream();
newImage.Save(newImageStream, ImageFormat.Jpeg);
}
return newImageStream;
}
///<summary>
/// 将一个内存流保存为磁盘文件。
///</summary>
///<param name="stream">内存流</param>
///<param name="newFile">目标磁盘文件地址</param>
public static void SaveStreamToFile(Stream stream, string newFile)
{
if (stream == null || stream.Length == 0 || string.IsNullOrEmpty(newFile))
{
return;
}
byte[] buffer = new byte[stream.Length];
stream.Position = 0;
stream.Read(buffer, 0, buffer.Length);
FileStream fileStream = new FileStream(newFile, FileMode.OpenOrCreate, FileAccess.Write);
fileStream.Write(buffer, 0, buffer.Length);
fileStream.Flush();
fileStream.Close();
fileStream.Dispose();
}
///<summary>
/// 对一个指定的图片加上图片水印效果。
///</summary>
///<param name="imageFile">图片文件地址</param>
///<param name="waterImage">水印图片(Image对象)</param>
public static void CreateImageWaterMark(string imageFile, System.Drawing.Image waterImage)
{
if (string.IsNullOrEmpty(imageFile) || !File.Exists(imageFile) || waterImage == null)
{
return;
}
System.Drawing.Image originalImage = System.Drawing.Image.FromFile(imageFile);
if (originalImage.Width - 10 < waterImage.Width || originalImage.Height - 10 < waterImage.Height)
{
return;
}
Graphics graphics = Graphics.FromImage(originalImage);
int x = originalImage.Width - waterImage.Width - 10;
int y = originalImage.Height - waterImage.Height - 10;
int width = waterImage.Width;
int height = waterImage.Height;
graphics.DrawImage(waterImage, new Rectangle(x, y, width, height), 0, 0, width, height, GraphicsUnit.Pixel);
graphics.Dispose();
MemoryStream stream = new MemoryStream();
originalImage.Save(stream, ImageFormat.Jpeg);
originalImage.Dispose();
System.Drawing.Image imageWithWater = System.Drawing.Image.FromStream(stream);
imageWithWater.Save(imageFile);
imageWithWater.Dispose();
}
///<summary>
/// 对一个指定的图片加上文字水印效果。
///</summary>
///<param name="imageFile">图片文件地址</param>
///<param name="waterText">水印文字内容</param>
public static void CreateTextWaterMark(string imageFile, string waterText)
{
if (string.IsNullOrEmpty(imageFile) || string.IsNullOrEmpty(waterText) || !File.Exists(imageFile))
{
return;
}
System.Drawing.Image originalImage = System.Drawing.Image.FromFile(imageFile);
Graphics graphics = Graphics.FromImage(originalImage);
graphics.SmoothingMode = SmoothingMode.HighQuality;
graphics.TextRenderingHint = TextRenderingHint.ClearTypeGridFit;
graphics.CompositingQuality = CompositingQuality.HighQuality;
graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
SolidBrush brush = new SolidBrush(Color.FromArgb(153, 255, 255, 255));
Font waterTextFont = new Font("Arial", 16, FontStyle.Regular);
SizeF waterTextSize = graphics.MeasureString(waterText, waterTextFont);
float x = (float)originalImage.Width - waterTextSize.Width - 10F;
float y = (float)originalImage.Height - waterTextSize.Height - 10F;
graphics.DrawString(waterText, waterTextFont, brush, x, y);
graphics.Dispose();
brush.Dispose();
MemoryStream stream = new MemoryStream();
originalImage.Save(stream, ImageFormat.Jpeg);
originalImage.Dispose();
System.Drawing.Image imageWithWater = System.Drawing.Image.FromStream(stream);
imageWithWater.Save(imageFile);
imageWithWater.Dispose();
}
- JavaScript 教程
- JavaScript 编辑工具
- JavaScript 与HTML
- JavaScript 与Java
- JavaScript 数据结构
- JavaScript 基本数据类型
- JavaScript 特殊数据类型
- JavaScript 运算符
- JavaScript typeof 运算符
- JavaScript 表达式
- JavaScript 类型转换
- JavaScript 基本语法
- JavaScript 注释
- Javascript 基本处理流程
- Javascript 选择结构
- Javascript if 语句
- Javascript if 语句的嵌套
- Javascript switch 语句
- Javascript 循环结构
- Javascript 循环结构实例
- Javascript 跳转语句
- Javascript 控制语句总结
- Javascript 函数介绍
- Javascript 函数的定义
- Javascript 函数调用
- Javascript 几种特殊的函数
- JavaScript 内置函数简介
- Javascript eval() 函数
- Javascript isFinite() 函数
- Javascript isNaN() 函数
- parseInt() 与 parseFloat()
- escape() 与 unescape()
- Javascript 字符串介绍
- Javascript length属性
- javascript 字符串函数
- Javascript 日期对象简介
- Javascript 日期对象用途
- Date 对象属性和方法
- Javascript 数组是什么
- Javascript 创建数组
- Javascript 数组赋值与取值
- Javascript 数组属性和方法
- 纯CSS实现自定义单选框和复选框
- 基于Linux安装Mysql5.7
- 纯CSS实现iOS风格打开关闭选择框
- 算法基础:递归
- ELK日志收集原理+es集群+elk搭建+本地目录文件读取,搭建分布式日志收集系统
- 什么是JavaScript 的闭包???
- es集群+elk搭建+kafka搭建分布式日志收集系统
- 设计模式(2)[JS版]---JavaScript如何实现单例模式?
- 算法基础:分治
- 黑客帝国中代码雨如何实现?用 canvas 轻松实现代码雨炫酷效果!
- 设计模式(3)[JS版]-JavaScript中的构造函数模式是什么?
- 基于docker 安装elasticsearch + kibana + ik分词器(6.7.2版本)
- 算法基础:排序
- 算法基础:动态规划
- 什么是 “并查集” ?