Windows Mobile引路蜂地图开发示例：二维图形库
jerry 地图开发 2015年11月26日
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Windows Mobile引路蜂地图开发包带有一个高效二维图形库，这是因为诸如LineCap, LineJoin, Brush, TextBrush, Path 等方法在Windows .Net Compact Framework 平台上不支持。Windows Mobile引路蜂地图开发包中的二维图形库弥补了这些缺陷，它提供了在桌面平台System.Drawing.Drawing2D中相应功能。
引路蜂地图开发包使用了这个图形库来绘制路径以及矢量地图。
基本知识
二维图形库使用类Graphics2D作为画板，内部画板实际为一个整数型二维数组。这种设计可以实现平台无关性。在绘制好图形后，最终是要在屏幕上显示的。在Windows Mobile平台上没有提供直接绘制整数型二维数组的方法。下面是在Windows Mobile绘制数型二维数组的方法。数组中每个元素为一个32位整数，格式为 AAAARRRRGGGGBBBB，分别代表透明度，红色，绿色，蓝色。
/// <summary> /// Graphics 2D Object /// </summary> private readonly Graphics2D graphics2D; /// <summary> /// screen width /// </summary> private readonly int screenWidth; /// <summary> /// screen Height /// </summary> private readonly int screenHeight; ..... screenWidth = Width; screenHeight = Height; graphics2D = new Graphics2D(screenWidth, screenHeight);
private void MainForm_Paint(object sender, PaintEventArgs e)
{
DrawRGB(e.Graphics, graphics2D.Argb, 0, 0, screenWidth, screenHeight);
}
////////////////////////////////////////////////////////////////////////////
//--------------------------------- REVISIONS ------------------------------
// Date Name Tracking # Description
// --------- ------------------- ------------- ----------------------
// 24SEP2010 James Shen Code review
////////////////////////////////////////////////////////////////////////////
/// <summary>
/// Draws the RGB.
/// </summary>
/// <param name="graphics">The graphics.</param>
/// <param name="rgbData">The RGB data.</param>
/// <param name="x">The x.</param>
/// <param name="y">The y.</param>
/// <param name="w">The w.</param>
/// <param name="h">The h.</param>
private static void DrawRGB(Graphics graphics, int[] rgbData, int x,
int y, int w, int h)
{
Bitmap bmp = new Bitmap(w, h);
System.Drawing.Rectangle rect =
new System.Drawing.Rectangle(0, 0, bmp.Width, bmp.Height);
BitmapData bmpData =
bmp.LockBits(rect, ImageLockMode.ReadWrite, PixelFormat.Format32bppRgb);
IntPtr ptr = bmpData.Scan0;
System.Runtime.InteropServices.Marshal.Copy(rgbData, 0, ptr, rgbData.Length);
bmp.UnlockBits(bmpData);
graphics.DrawImage(bmp, x, y);
}
下面简单介绍一下图形库，功能基本和桌面平台类似。
颜色
/**
* The solid (full opaque) red color in the ARGB space
*/
Color redColor = new Color(0xffff0000, false);
/**
* The semi-opaque green color in the ARGB space (alpha is 0x78)
*/
Color greenColor = new Color(0x7800ff00, true);
/**
* The semi-opaque blue color in the ARGB space (alpha is 0x78)
*/
Color blueColor = new Color(0x780000ff, true);
/**
* The semi-opaque yellow color in the ARGB space ( alpha is 0x78)
*/
Color yellowColor = new Color(0x78ffff00, true);
/**
* The dash array
*/
int[] dashArray = { 20, 8 };
graphics2D.Reset();
graphics2D.Clear(Color.Black);
SolidBrush brush = new SolidBrush(redColor);
graphics2D.FillOval(brush, 30, 60, 80, 80);
brush = new SolidBrush(greenColor);
graphics2D.FillOval(brush, 60, 30, 80, 80);
Pen pen = new Pen(yellowColor, 10, Pen.CapButt, Pen.JoinMiter, dashArray, 0);
brush = new SolidBrush(blueColor);
graphics2D.SetPenAndBrush(pen, brush);
graphics2D.FillOval(null, 90, 60, 80, 80);
graphics2D.DrawOval(null, 90, 60, 80, 80);
Invalidate();
线段接头(LineCap)
Color blackColor = new Color(0x000000); Color whiteColor = new Color(0xffffff); graphics2D.Reset(); graphics2D.Clear(Color.White); Pen pen = new Pen(blackColor, 20, Pen.CapButt, Pen.JoinMiter); graphics2D.DrawLine(pen, 40, 60, 140, 60); pen = new Pen(whiteColor, 1); graphics2D.DrawLine(pen, 40, 60, 140, 60); pen = new Pen(blackColor, 20, Pen.CapRound, Pen.JoinMiter); graphics2D.DrawLine(pen, 40, 100, 140, 100); pen = new Pen(whiteColor, 1); graphics2D.DrawLine(pen, 40, 100, 140, 100); pen = new Pen(blackColor, 20, Pen.CapSquare, Pen.JoinMiter); graphics2D.DrawLine(pen, 40, 140, 140, 140); pen = new Pen(whiteColor, 1); graphics2D.DrawLine(pen, 40, 140, 140, 140); Invalidate();
梨子
最后一个例子是利用各种几何图形通过“加”，“减”，“并”操作组成一个梨子图形。
Ellipse circle, oval, leaf, stem; Area circ, ov, leaf1, leaf2, st1, st2; circle = new Ellipse(); oval = new Ellipse(); leaf = new Ellipse(); stem = new Ellipse(); circ = new Area(circle); ov = new Area(oval); leaf1 = new Area(leaf); leaf2 = new Area(leaf); st1 = new Area(stem); st2 = new Area(stem); graphics2D.Reset(); graphics2D.Clear(Color.White); int w = screenWidth; int h = screenHeight; int ew = w / 2; int eh = h / 2; SolidBrush brush = new SolidBrush(Color.Green); graphics2D.DefaultBrush = brush; // Creates the first leaf by filling the intersection of two Area //objects created from an ellipse. leaf.SetFrame(ew - 16, eh - 29, 15, 15); leaf1 = new Area(leaf); leaf.SetFrame(ew - 14, eh - 47, 30, 30); leaf2 = new Area(leaf); leaf1.Intersect(leaf2); graphics2D.Fill(null, leaf1); // Creates the second leaf. leaf.SetFrame(ew + 1, eh - 29, 15, 15); leaf1 = new Area(leaf); leaf2.Intersect(leaf1); graphics2D.Fill(null, leaf2); brush = new SolidBrush(Color.Black); graphics2D.DefaultBrush = brush; // Creates the stem by filling the Area resulting from the //subtraction of two Area objects created from an ellipse. stem.SetFrame(ew, eh - 42, 40, 40); st1 = new Area(stem); stem.SetFrame(ew + 3, eh - 47, 50, 50); st2 = new Area(stem); st1.Subtract(st2); graphics2D.Fill(null, st1); brush = new SolidBrush(Color.Yellow); graphics2D.DefaultBrush = brush; // Creates the pear itself by filling the Area resulting from the //union of two Area objects created by two different ellipses. circle.SetFrame(ew - 25, eh, 50, 50); oval.SetFrame(ew - 19, eh - 20, 40, 70); circ = new Area(circle); ov = new Area(oval); circ.Add(ov); graphics2D.Fill(null, circ); Invalidate();
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