由于经常需要基于固定的一个模板底图,生成微信小程序分享用的海报图,如果每次都调用绘图函数,手动编写每个placeholder的填充,重复而且容易出错,因此,封装一个TemplateImage,用于填充每个需要画上数据的地方,
先看看调用的方式:
_homeShareTemplate.Generate(new TemplateItem[] //Generate返回新的Bitmap
{
new StringTemplateItem() //日期
{
Location = new Point(80 * 2, 78*2),
Font = new Font("宋体", 42, FontStyle.Bold, GraphicsUnit.Pixel),
Color = Color.FromArgb(0x8e, 0x1a, 0x22),
Value = DateTime.Now.ToString("yyyy.MM.dd"),
Horizontal = HorizontalPosition.Center
},
new StringTemplateItem() //农历
{
Location = new Point(230*2, 166*2),
//MaxWidth = 15,
Font = new Font("宋体", 22, FontStyle.Bold, GraphicsUnit.Pixel),
Color = Color.FromArgb(0x8e, 0x1a, 0x22),
StringFormat = new StringFormat(StringFormatFlags.DirectionVertical),
Value = GetMonthCalendar(DateTime.Now)
},
new StringTemplateItem() //星期
{
Location = new Point(256*2, 175*2),
//MaxWidth = 15,
Font = new Font("宋体", 24, FontStyle.Bold, GraphicsUnit.Pixel),
Color = Color.FromArgb(0x8e, 0x1a, 0x22),
StringFormat = new StringFormat(StringFormatFlags.DirectionVertical),
Value = GetWeekName(DateTime.Now)
},
new ImageTemplateItem() //图片
{
Image = (Bitmap) Bitmap.FromFile(Path.Join(Directory.GetCurrentDirectory(),weather.MainImageUrl)),
Location = new Point(81*2, 108*2),
Size = new Size(132*2, 133*2)
},
new StringTemplateItem()
{
Location = new Point(88*2, 257*2),
MaxWidth = 125*2,
Font = new Font("楷体", 30, FontStyle.Bold, GraphicsUnit.Pixel),
Color = Color.FromArgb(0x17, 0x14, 0x0e),
Value = weather.Content.Left(44)
},
new StringTemplateItem() //宜
{
Location = new Point(35*2+3,294*2),
Color = Color.FromArgb(0x8f, 0x1A, 0x22),
Font = new Font("宋体", 38, FontStyle.Bold, GraphicsUnit.Pixel),
StringFormat = new StringFormat(StringFormatFlags.DirectionVertical),
//MaxWidth = 14,
Value = weather.Yi.Left(4)
},
new StringTemplateItem() //忌
{
Location = new Point(228*2+3,294*2),
Color = Color.FromArgb(0x8f, 0x1A, 0x22),
Font = new Font("宋体", 38, FontStyle.Bold, GraphicsUnit.Pixel),
StringFormat = new StringFormat(StringFormatFlags.DirectionVertical),
//MaxWidth = 14,
Value = weather.Ji.Left(4)
},
new QrCodeTemplateItem() //二维码
{
Location = new Point(188*2, 421*2),
Size = new Size(73*2, 72*2),
QrCode = "http://ssssss.com/sdfsdfsdfs/sss"
}
});
输出的效果如下:
完整的功能由一个TemplateImage作为模板图管理的类+N个根据需要输出的各种数据处理类,可根据实际需求进行扩展不同的类型,默认有:String,Image,QrCode三种:
单个模板图管理类的定义:
public class TemplateImage:IDisposable
{
private Bitmap _templateSource = null;
private Stream _sourceStream = null;
private FileSystemWatcher _wather = null;
public TemplateImage(Bitmap templateSource)
{
_templateSource = templateSource;
}
/// <summary>
/// 模板图片的构造函数
/// </summary>
/// <param name="templatePath">模板图片文件绝对路径</param>
/// <param name="isWatchFileModify">是否自动监控文件,当文件有变动时,自动重新加载模板文件
/// </param>
public TemplateImage(string templatePath,bool isWatchFileModify=true)
{
if (!File.Exists(templatePath))
{
throw new FileNotFoundException(nameof(templatePath));
}
//打开模板文件路径,在跳出构造函数后,自动释放file对象,防止长久占用文件,导致无法替换模板文件
using var file = File.OpenRead(templatePath);
var data = file.ReadAllBytes();
var s1 = new ByteStream(data); //这里s1肯定不能关闭,否则,再调用Bitmap.Clone函数的时候,会报错
_sourceStream = s1;
_templateSource = (Bitmap) Bitmap.FromStream(s1);
if (isWatchFileModify) //如果启用文件监控,则自动监控模板图片文件
{
_wather = new FileSystemWatcher(templatePath);
_wather.EnableRaisingEvents = true;
_wather.Changed += wather_changed;
}
}
private void wather_changed(object sender, FileSystemEventArgs e)
{
if (e.ChangeType == WatcherChangeTypes.Changed || e.ChangeType== WatcherChangeTypes.Created )
{
using var file = File.OpenRead(e.FullPath);
var data = file.ReadAllBytes();
var oldValue = _sourceStream;
var templateSource = _templateSource;
var s1 = new ByteStream(data);
var newTemplateSource = (Bitmap) Bitmap.FromStream(s1);
_sourceStream = s1;
_templateSource = newTemplateSource;
oldValue.Close();
oldValue.Dispose();
templateSource.Dispose();
}
}
public SmoothingMode SmoothingMode { set; get; } = SmoothingMode.AntiAlias;
public TextRenderingHint TextRenderingHint { set; get; } = TextRenderingHint.AntiAlias;
public CompositingQuality CompositingQuality { set; get; } = CompositingQuality.HighQuality;
/// <summary>
/// 根据传入的数据,套入模板图片,生成新的图片
/// </summary>
/// <param name="settings"></param>
/// <returns></returns>
public Bitmap Generate(TemplateItemBase[] settings)
{
//Clone一个新的Bitmap对象
var newImg = (Bitmap)_templateSource.Clone();
var g1 = Graphics.FromImage(_templateSource);
try
{
using (var g = Graphics.FromImage(newImg))
{
g.SmoothingMode = SmoothingMode;
g.TextRenderingHint = TextRenderingHint;
g.CompositingQuality = CompositingQuality;
foreach (var item in settings)
{
item.Draw(g, newImg.Size); //调用每个Item的Draw画入新的数据
}
return newImg;
}
}
catch (Exception e)
{
Console.WriteLine(e);
throw;
}
}
public void Dispose()
{
_templateSource.Dispose();
_sourceStream?.Close();
_sourceStream?.Dispose();
}
}
至此,一个模板图片类已定义完成,接下来需要定义一个Placeholder的基类:
1 public abstract class TemplateItemBase
2 {
3 /// <summary>
4 /// 水平方向对其方式,默认为Custom,使用Location定位
5 /// </summary>
6 public HorizontalPosition Horizontal { set; get; } = HorizontalPosition.Custom;
7
8 /// <summary>
9 /// 垂直方向对其方式,默认为Custom,使用Location定位
10 /// </summary>
11 public VerticalPosition Vertical { set; get; } = VerticalPosition.Custom;
12
13 /// <summary>
14 /// 输出项定位
15 /// </summary>
16 public Point Location { set; get; }
17
18 public abstract void Draw(Graphics graphics,Size newBitmapSize);
19
20 }
这个基类定义了每个placeholder的定位方式,Custom表示使用Location自定义位置.
然后开始来定义每个不同类型的TemplateItem:
1.String类型:
1 /// <summary>
2 /// 普通字符串项
3 /// </summary>
4 public class StringTemplateItem : TemplateItemBase
5 {
6 /// <summary>
7 /// 文本字符串值
8 /// </summary>
9 public string Value { set; get; }
10
11 /// <summary>
12 /// 字体信息
13 /// </summary>
14 public Font Font { set; get; }
15
16 /// <summary>
17 /// 字体颜色
18 /// </summary>
19 public Color Color { set; get; }= Color.Black;
20
21 /// <summary>
22 /// 文本输出的最大宽度,如果为0,则自动,,如果非0,则只用最大宽度,并自动根据最大宽度修改计算字符串所需高度
23 /// </summary>
24 public int MaxWidth { set; get; } = 0;
25
26 /// <summary>
27 /// 字符串输出参数
28 /// </summary>
29 /// <example>
30 /// 如纵向输出:
31 /// new StringFormat(StringFormatFlags.DirectionVertical)
32 ///
33 /// </example>
34 public StringFormat StringFormat { set; get; }
35
36 public override void Draw(Graphics graphics,Size newBitmapSize)
37 {
38 var location = this.Location;
39 SizeF size=default(Size);
40 if (this.Horizontal== HorizontalPosition.Center || this.Vertical== VerticalPosition.Middle)
41 {
42 location = new Point(this.Location.X,this.Location.Y);
43
44 if (this.MaxWidth>0)
45 {
46 size = graphics.MeasureString(this.Value, this.Font,this.MaxWidth);
47 }
48 else
49 {
50 size = graphics.MeasureString(this.Value, this.Font);
51 }
52
53 if (this.Horizontal== HorizontalPosition.Center)
54 {
55 var newx = newBitmapSize.Width / 2 - (int)(size.Width / 2);
56 location.X = newx;
57 }
58
59 if (this.Vertical== VerticalPosition.Middle)
60 {
61 var newy= newBitmapSize.Height / 2 - (int)(size.Height / 2);
62 location.Y = newy;
63 }
64 }
65 else if(MaxWidth>0)
66 {
67 size = graphics.MeasureString(this.Value, this.Font,this.MaxWidth);
68 }
69
70 if (MaxWidth>0)
71 {
72 graphics.DrawString(this.Value, this.Font,new SolidBrush(this.Color), new RectangleF(location,size),StringFormat);
73 }
74 else
75 {
76 graphics.DrawString(this.Value, this.Font,new SolidBrush(this.Color), location,StringFormat);
77 }
78
79
80 }
81 }
2.纯图片类型:
1 /// <summary>
2 /// 传入一个图片
3 /// </summary>
4 public class ImageTemplateItem:TemplateItemBase
5 {
6 /// <summary>
7 /// 图片数据
8 /// </summary>
9 public Bitmap Image { set; get; }
10
11 /// <summary>
12 /// 图片输出到模板图的时候的大小
13 /// </summary>
14 public Size Size { set; get; }
15
16 public override void Draw(Graphics graphics,Size newBitmapSize)
17 {
18 var location = this.Location;
19
20 //计算垂直居中或水平居中的情况下的定位
21 if (this.Horizontal== HorizontalPosition.Center || this.Vertical== VerticalPosition.Middle)
22 {
23 location = new Point(this.Location.X,this.Location.Y);
24
25 if (this.Horizontal== HorizontalPosition.Center)
26 {
27 var newx = newBitmapSize.Width / 2 - this.Size.Width / 2;
28
29 location.X = newx;
30 }
31
32 if (this.Vertical== VerticalPosition.Middle)
33 {
34 var newy= newBitmapSize.Height / 2 - this.Size.Height / 2;
35 location.Y = newy;
36 }
37 }
38
39 //此处后续可优化为使用Lockbits的方式
40 graphics.DrawImage(Image,new Rectangle(location,this.Size),new Rectangle(0,0,this.Image.Width,this.Image.Height),GraphicsUnit.Pixel);
41
42 }
43 }
3.QrCode的方式,使用QRCoder类库:
1 /// <summary>
2 /// 二维码项
3 /// </summary>
4 public class QrCodeTemplateItem : TemplateItemBase
5 {
6 /// <summary>
7 /// 二维码内实际存储的字符数据
8 /// </summary>
9 public string QrCode { set; get; }
10
11 /// <summary>
12 /// 二维码中心的icon图标
13 /// </summary>
14 public Bitmap Icon { set; get; }
15
16 /// <summary>
17 /// 二维码尺寸
18 /// </summary>
19 public Size Size { set; get; }
20
21 /// <summary>
22 /// 容错级别,默认为M
23 /// </summary>
24 public QRCodeGenerator.ECCLevel ECCLevel { set; get; } = QRCodeGenerator.ECCLevel.M;
25
26 public override void Draw(Graphics graphics,Size newBitmapSize)
27 {
28 var location = this.Location;
29
30 if (this.Horizontal== HorizontalPosition.Center || this.Vertical== VerticalPosition.Middle)
31 {
32 location = new Point(this.Location.X,this.Location.Y);
33
34 if (this.Horizontal== HorizontalPosition.Center)
35 {
36 var newx = newBitmapSize.Width / 2 - this.Size.Width / 2;
37
38 location.X = newx;
39 }
40
41 if (this.Vertical== VerticalPosition.Middle)
42 {
43 var newy= newBitmapSize.Height / 2 - this.Size.Height / 2;
44 location.Y = newy;
45 }
46 }
47
48 using (QRCodeGenerator qrGenerator = new QRCodeGenerator())
49 using (QRCodeData qrCodeData = qrGenerator.CreateQrCode(QrCode,ECCLevel))
50 using (QRCode qrCode = new QRCode(qrCodeData))
51 using (Bitmap qrCodeImage = qrCode.GetGraphic(20,Color.Black,Color.White,Icon))
52 {
53 graphics.DrawImage(qrCodeImage,new Rectangle(location,this.Size),new Rectangle(0,0,qrCodeImage.Width,qrCodeImage.Height),GraphicsUnit.Pixel);
54
55 }
56 }
57 }
后续的优化:
1.Image画入的优化处理,考虑是否可以用Lockbits进行优化
2.增加不同类型的新的Item
完整的代码详见:https://github.com/kugarliyifan/Kugar.Core/blob/master/Kugar.Core.NetCore/Images/TemplateImage.cs
