一、显示图形图像
对图像文件的显示过程：
(1)创建Image类（如Bitmap）、Graphics烊的对象
（2）用Graphics.DrawImage绘制
图形文件格式：
Bmp 与存储设置和应用程序无关的图像。每位像素位数（1、4、8、15、24、32、64）在
文件头中指定。24位Bmp是通用的。
GIF Web通用格式。适用线、纯色、边界清晰图片。是无损压缩。可指定一色为透明。
JPEG 24位，有损压缩（肉眼难辨），不支持透明。
EXIF 数码相机照片格式，据JPEG压缩，还包括日期、曝光时间、相机等信息。
PNG 无损压缩（同GIF），以8、24、48位存储颜色，并以1、2、4、8、16位存储灰度
为每像素存储Alpha值。还可含Gamma及颜色校正，可精确显示图像。
TIFF 各平台及程序均支持，以每像素任意位存储图像，压缩算法多样。灵活性好
'01.DrawImage绘制图片文件' 共有30个重载。从原始图上的一部分或全部 画到 目标上的某位置或区域imports System.DrawingPublic Class Form1 Private Sub button1_Click(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles button1.Click Dim gr As Graphics = Me.CreateGraphics Dim bm As New Bitmap("D:.jpg") '指定位置画原始图的全部 gr.DrawImage(bm,New Point(10,5)) '指定位置区域画原始图（有缩放功能） gr.Translatetransform(200,5) gr.DrawImage(bm,New Rectangle(0,80,80)) '取原始图部分进行画(无缩放） gr.Translatetransform(100,0) gr.DrawImage(bm,New RectangleF(0,30,60,60),GraphicsUnit.Pixel) '取原始图部分在目标上某区域绘制（缩放） gr.Translatetransform(-280,150) gr.DrawImage(bm,100,110),GraphicsUnit.Pixel) End SubEnd Class
'02.Clone 克隆'克隆受参数像素格式影响，成图不同imports System.DrawingPublic Class Form1 Private Sub button1_Click(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles button1.Click Dim gr As Graphics = Me.CreateGraphics Dim bm As New Bitmap("D:.bmp") '原图 gr.DrawImage(bm,5)) Dim bm1 As Bitmap = bm.Clone(New Rectangle(0,40,50),Imaging.PixelFormat.Format24bppRgb) gr.Translatetransform(180,5) gr.DrawImage(bm1,0) '为了看清clone不再缩放 Dim bm2 As Bitmap = bm.Clone(New Rectangle(40,Imaging.PixelFormat.Format24bppRgb) gr.Translatetransform(80,0) gr.DrawImage(bm2,0) '下面是像素不同时的展现 Dim bm3 As Bitmap = bm.Clone(New Rectangle(40,Imaging.PixelFormat.Format16bppArgb1555) gr.Translatetransform(-250,150) gr.DrawImage(bm3,0) Dim bm4 As Bitmap = bm.Clone(New Rectangle(40,Imaging.PixelFormat.Format4bppIndexed) gr.Translatetransform(110,0) gr.DrawImage(bm4,0) Dim bm5 As Bitmap = bm.Clone(New Rectangle(40,Imaging.PixelFormat.Format1bppIndexed) gr.Translatetransform(110,0) gr.DrawImage(bm5,0) Dim bm6 As Bitmap = bm.Clone(New Rectangle(40,Imaging.PixelFormat.Format8bppIndexed) gr.Translatetransform(110,0) gr.DrawImage(bm6,0) End SubEnd Class
'03 Maketransparent 使某色透明' 先取得某颜色GetPixel，然后用maketransparent进行透明imports System.Drawing.drawing2dPublic Class Form1 '为了便于查看，窗体背景设置为黄色 Private Sub button1_Click(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles button1.Click Dim gr As Graphics = Me.CreateGraphics '取色 Dim bm As New Bitmap("D:.bmp") Dim col As color = bm.GetPixel(1,1) '画原始图 gr.DrawImage(bm,10,10) '透明 bm.Maketransparent(col) gr.DrawImage(bm,280,10) gr.DrawRectangle(Pens.Red,New Rectangle(280,bm.WIDth,bm.Height)) '原来的外框 End SubEnd Class
'04 用ico图像绘制图形' 先用ico构造TextureBrush,然后再构造Pen，最后画图形imports System.Drawingimports System.Drawing.drawing2dPublic Class Form1 Private Sub button1_Click(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles button1.Click Dim gr As Graphics = Me.CreateGraphics Dim bm As New Bitmap("d:.ico") Dim tb As New Drawing.TextureBrush(bm) Dim myPen As New Pen(tb,20) gr.DrawImage(bm,10) gr.DrawEllipse(myPen,New Rectangle(40,200,100)) End SubEnd Class
二、图像变换
1、Image对象的RotateFlip方法可以旋转和翻转。
Rotate旋转， Flip翻转
须先用Image.Fromfile（Str）等方法加载图像文件
'05.图像的旋转与翻转:Image.RotateFlip
'旋转都是顺时针
Public Class Form1 Private Sub button1_Click(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles button1.Click Dim gr As Graphics = Me.CreateGraphics Dim img As Image = Image.Fromfile("D:.jpg") gr.DrawImage(img,New Point(0,0)) img.RotateFlip(RotateFlipType.Rotate90FlipNone) '2.顺时针转90 gr.DrawImage(img,New Point(130,0)) '每次变换都是从上一次变换 img.RotateFlip(RotateFlipType.Rotate90FlipX) '3.先转90再X翻转 gr.DrawImage(img,New Point(260,0)) img.RotateFlip(RotateFlipType.Rotate90FlipY) ' 4.先转90再Y翻转 gr.DrawImage(img,New Point(390,0)) img.RotateFlip(RotateFlipType.RotateNoneFlipX) ' 5.X翻转 gr.DrawImage(img,130)) img.RotateFlip(RotateFlipType.RotateNoneFlipY) '6.Y翻转 gr.DrawImage(img,130)) img.Save("D:.bmp") '最后形变 End SubEnd Class
'06.对图形的反射、扭曲'关键在定义目标区域，目标区域由平行四边形定义（取三个点，第四点自动计算）'三点：左上角、左下角，右上角。imports System.Drawingimports System.Drawing.drawing2dPublic Class Form1 Private Sub button1_Click(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles button1.Click Dim bm As New Bitmap("D:.jpg") Dim gr As Graphics = Me.CreateGraphics Dim bm1 As New Bitmap(bm.WIDth,bm.Height) Dim gr1 As Graphics = Graphics.FromImage(bm1) Dim p As Point() = {New Point(100,0),New Point(200,50)} gr.DrawImage(bm,0)) '原图在窗体上 '示意图:bm上有图，通过绘制（变形）到bm1(原先有空白，现在有图），最后显示在窗体上 gr1.DrawImage(bm,p) '先把bm变形画到bm1上(要注意bm1能容纳bm变形后的图形,例中专门不能容纳全部变形后图形） gr.DrawImage(bm1,150)) '再把bm1画上窗体上 bm1.Save("D:.jpg") '变形图形存盘 End SubEnd Class
'07.插值模式缩放 Graphics.InterPolationModeimports System.Drawingimports System.Drawing.drawing2dPublic Class Form1 Private Sub button1_Click(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles button1.Click Dim gr As Graphics = Me.CreateGraphics Dim bm As New Bitmap("d:.jpg") Dim src As New Rectangle(0,bm.Height) Dim dec As New Rectangle(0,0.5 * bm.WIDth,0.5 * bm.Height) gr.DrawImage(bm,src,GraphicsUnit.Pixel) '原图 gr.Translatetransform(160,dec,GraphicsUnit.Pixel) '缺省 gr.InterpolationMode = drawing2d.InterpolationMode.Bicubic gr.Translatetransform(80,GraphicsUnit.Pixel) gr.InterpolationMode = drawing2d.InterpolationMode.High gr.Translatetransform(80,GraphicsUnit.Pixel) gr.InterpolationMode = drawing2d.InterpolationMode.Low gr.Translatetransform(80,GraphicsUnit.Pixel) End SubEnd Class
'08.纹理填充图形（如椭圆）'主要用TextureBrush，并可对纹理缩放imports System.Drawingimports System.Drawing.drawing2dPublic Class Form1 Private Sub button1_Click(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles button1.Click Dim gr As Graphics = Me.CreateGraphics Dim bm As New Bitmap("d:.jpg") Dim tBrush As New TextureBrush(bm) gr.FillEllipse(tBrush,300,150)) tBrush.Scaletransform(0.5F,0.5F) '可对纹理进行缩放等坐标变换 gr.FillEllipse(tBrush,150,150)) End SubEnd Class
'09.Graphics.BeginContainer ' Graphics.EndContainer'图形容器：“装载”或“容纳”图形数据（包括坐标）的“容器”。比如窗口（0，0）就是默认的容器。'BeginContainer将保存先前的容器（数据到堆栈上，并设置标识），开始新的一容器。'EndContainer 结束当前容器，并返回上一个beginContainer保存的数据。'EndContainer之前可以有多个BeginContainer，但只能返回上一次容器数据(并移除堆栈上数据）imports System.Drawingimports System.Drawing.drawing2dPublic Class Form1 Private Sub button1_Click(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles button1.Click Dim gr As Graphics = Me.CreateGraphics Dim grContainer As GraphicsContainer '定位，便于观看后面位置变化 gr.DrawRectangle(Pens.Black,New Rectangle(50,50,50)) gr.Translatetransform(50,50) 'A grContainer = gr.BeginContainer '存储以前数据，开始创建容器 gr.Translatetransform(0,40) gr.FillRectangle(Brushes.Red,20,60)) gr.EndContainer(grContainer) '恢复存储前容器，所以坐标返回到A处 gr.FillRectangle(Brushes.Blue,20)) End SubEnd Class
'10.EndContainer（gc)还原某状态前的容器' gr.restore 还原原始容器，删除堆栈上的信息imports System.Drawing.drawing2dPublic Class Form1 Private Sub button1_Click(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles button1.Click Dim gr As Graphics = Me.CreateGraphics Dim gc1 As GraphicsContainer Dim gc2 As GraphicsContainer gc1 = gr.BeginContainer gr.Translatetransform(50,50) gr.FillRectangle(Brushes.Blue,50)) gc2 = gr.BeginContainer gr.Translatetransform(50,50) gr.FillRectangle(Brushes.Red,60)) gr.EndContainer(gc2) gr.FillRectangle(Brushes.Black,40)) gr.EndContainer(gc1) gr.FillRectangle(Brushes.Red,30)) End SubEnd Class总结
以上是内存溢出为你收集整理的笔记10: 变换图像全部内容，希望文章能够帮你解决笔记10: 变换图像所遇到的程序开发问题。
如果觉得内存溢出网站内容还不错，欢迎将内存溢出网站推荐给程序员好友。
欢迎分享，转载请注明来源：内存溢出
微信扫一扫
支付宝扫一扫
评论列表（0条）