《GDI+系列教程》第5章 —— 纹理画刷的效果

《GDI+系列教程》的作者：空

在《GDI+系列教程》前4章里，我不厌其烦的向大家解释了几乎每一句代码的作用、由来、概念等等，并且总结了相应的使用定式。这是因为刚入门，很多东西需要有一个熟悉的过程。

从本章开始，入门算是结束了，咱得开始提高了。所以我们将直接使用之前总结好的定式，并且任何旧知识，都尽量简言带过，只重点讲述新内容。

本章，我们会在屏幕上画一堆圆，演示纹理画刷的效果。

1.使用定式直接创建出画布并准备画圆

#SingleInstance, Force
#NoEnv
SetBatchLines, -1
; Uncomment if Gdip.ahk is not in your standard library
#Include, Gdip_All.ahk
; 初始化 gdi+ 需要的一切
gosub, init
; Set a timer to draw a new ellipse every 2000ms
; 使用纹理画刷画圆
SetTimer, DrawCircle, 2000
Return

2.随机设置纹理样式等参数

DrawCircle:
; Get a random colour for the background and foreground of hatch style used to fill the ellipse,
; as well as random brush style, x and y coordinates and width/height
; 随机生成圆的参数
; 这里将透明度固定为 0xff 即不透明，否则随机生成的数范围太大，又常常夹带透明度，造成看起来都是白色的。
Random, RandBackColour, 0xff000000, 0xffffffff
Random, RandForeColour, 0xff000000, 0xffffffff
; 纹理样式
Random, RandBrush, 0, 53
; 圆的高宽 设置大一点，才看得清里面的纹理
Random, RandElipseWidth, 200, 300
Random, RandElipseHeight, 200, 300
; 圆的坐标
Random, RandElipsexPos, %WALeft%, % WAWidth-RandElipseWidth
Random, RandElipseyPos, %WATop%, % WAHeight-RandElipseHeight

3.使用随机纹理样式等参数画圆

; Create the random brush
; 创建纹理画刷 又叫影线画刷 Gdip_BrushCreateHatch(背景色, 前景色, 样式)
pBrush := Gdip_BrushCreateHatch(RandBackColour, RandForeColour, RandBrush)
; Fill the graphics of the bitmap with an ellipse using the brush created
; 填充圆
Gdip_FillEllipse(G, pBrush, RandElipsexPos, RandElipseyPos, RandElipseWidth, RandElipseHeight)
; Update the specified window
; 显示出来
UpdateLayeredWindow(hwnd1, hdc, WALeft, WATop, WAWidth, WAHeight)
; Delete the brush as it is no longer needed and wastes memory
; 刷子用完了，要立刻释放资源。在本例中，实际效果来讲，放 Exitgdip 标签里也一样，但放这里主要是提醒大家，即用即释放，就像随手关门一样！
Gdip_DeleteBrush(pBrush)
Return

4.收工善后

ExitGdip:
  ; Select the object back into the hdc
  SelectObject(hdc, obm)
  ; Now the bitmap may be deleted
  DeleteObject(hbm)
  ; Also the device context related to the bitmap may be deleted
  DeleteDC(hdc)
  ; The graphics may now be deleted
  Gdip_DeleteGraphics(G)
  ; ...and gdi+ may now be shutdown
  Gdip_Shutdown(pToken)
  ExitApp
Return

0.定式

init:
  ; 以下都是初始化定式
  ; Start gdi+
  If !pToken := Gdip_Startup()
  {
    MsgBox, 48, gdiplus error!, Gdiplus failed to start. Please ensure you have gdiplus on your system
    ExitApp
  }
  OnExit, ExitGdip
  ; Get the dimensions of the primary monitor
  ; 将作画范围设置为整个屏幕
  SysGet, MonitorPrimary, MonitorPrimary
  SysGet, WA, MonitorWorkArea, %MonitorPrimary%
  WAWidth := WARight-WALeft
  WAHeight := WABottom-WATop
  ; Create a layered window (+E0x80000) that is always on top (+AlwaysOnTop), has no taskbar entry or caption
  Gui, 1: -Caption +E0x80000 +LastFound +AlwaysOnTop +ToolWindow +OwnDialogs
  ; Show the window
  Gui, 1: Show, NA
  ; Get a handle to this window we have created in order to update it later
  hwnd1 := WinExist()
  ; Create a gdi bitmap with width and height of the work area
  hbm := CreateDIBSection(WAWidth, WAHeight)
  ; Get a device context compatible with the screen
  hdc := CreateCompatibleDC()
  ; Select the bitmap into the device context
  obm := SelectObject(hdc, hbm)
  ; Get a pointer to the graphics of the bitmap, for use with drawing functions
  G := Gdip_GraphicsFromHDC(hdc)
  ; Set the smoothing mode to antialias = 4 to make shapes appear smother (only used for vector drawing and filling)
  Gdip_SetSmoothingMode(G, 4)
Return

本章习题：画一个棋盘出来。（主要是这个纹理）

全部代码与库文件下载地址：

https://ahk.lanzoux.com/b01nypnuh

密码:1234