如何创建[圆角、边框色彩渐变、边框宽度自定义]窗体

先让大家看一下我要实现的窗体效果：

该窗体的背景色、圆角半径(下面代码中将圆角半径等于边框宽度，此为为般化处理，参考者可视具体需要而对代码略作修改，使二者具有不同的值，以获得不同的效果）由用户根据需要改变。上、左边框的色彩为白色(其实为DrawEdge过程中colTopLef决定，可设为其他值)到窗体背景色的渐变，下、右边框的色彩为RGB(132, 132, 132)(其实为DrawEdge过程中colBottomRight所决定，也可设为其他值)到窗体背景色的渐变。

要实现该效果，你的窗体（对任拥有hWnd属性的对象，也一样实用）应作如下设置：
1——BorderStyle=0,
2——ScaleMode=3 (所有GDI类API使用的长度单位都为Pixel，对应于该项的设置）。
3——AutoRedraw=True

主要使用了三个过程：
Windowshape ——'重塑窗体轮廓，入口函数，调用后两个函数
MakeRoundCorner——圆角
DrawEdge ——画外框

以下代码为要实现特效的窗体中的代码：
===============================================================
Private Sub Form_Load()
'调用入口函数实现效果
WindowShape hwnd, hdc, BackColor, ScaleWidth + 1, ScaleHeight + 1, 10
'将窗体置顶，
SetWindowPos Me.hwnd, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOACTIVATE Or SWP_SHOWWINDOW Or SWP_NOMOVE Or SWP_NOSIZE
End Sub
===============================================================

以下为具体实现代码，可置于一个module中：
===============================================================
Option Explicit

Private Declare Function SetWindowRgn Lib "user32" (ByVal hwnd As Long, ByVal hRgn As Long, ByVal bRedraw As Boolean) As Long
Private Declare Function CombineRgn Lib "gdi32" (ByVal hDestRgn As Long, ByVal hSrcRgn1 As Long, ByVal hSrcRgn2 As Long, ByVal nCombineMode As Long) As Long
Private Declare Function CreateRoundRectRgn Lib "gdi32" (ByVal X1 As Long, ByVal Y1 As Long, ByVal X2 As Long, ByVal Y2 As Long, ByVal X3 As Long, ByVal Y3 As Long) As Long
Private Declare Function CreateSolidBrush Lib "gdi32" (ByVal crColor As Long) As Long

Private Declare Function SelectObject Lib "gdi32" (ByVal hdc As Long, ByVal hObject As Long) As Long
Private Declare Function DeleteObject Lib "gdi32" (ByVal hObject As Long) As Long
Private Declare Function StretchBlt Lib "gdi32" (ByVal hdc As Long, ByVal X As Long, ByVal Y As Long, ByVal nWidth As Long, ByVal nHeight As Long, ByVal hSrcDC As Long, ByVal xSrc As Long, ByVal ySrc As Long, ByVal nSrcWidth As Long, ByVal nSrcHeight As Long, ByVal dwRop As Long) As Long
Private Declare Function CopyRect Lib "user32" (lpDestRect As RECT, lpSourceRect As RECT) As Long

Private Declare Function GradientFill Lib "gdi32" Alias "GdiGradientFill" (ByVal hdc As Long, pVertex As TRIVERTEX, ByVal dwNumVertex As Long, pMesh As GRADIENT_RECT, ByVal dwNumMesh As Long, ByVal dwMode As Long) As Long
Private Declare Function GradientFillTriangle Lib "msimg32" Alias "GradientFill" (ByVal hdc As Long, pVertex As TRIVERTEX, ByVal dwNumVertex As Long, pMesh As GRADIENT_TRIANGLE, ByVal dwNumMesh As Long, ByVal dwMode As Long) As Long
Private Declare Function OleTranslateColor Lib "olepro32.dll" (ByVal OLE_COLOR As Long, ByVal hPalette As Long, pccolorref As Long) As Long
Private Declare Function RtlMoveMemory Lib "kernel32.dll" (Destination As Any, Source As Any, ByVal Length As Long) As Long
Public Declare Function SetWindowPos Lib "user32" (ByVal hwnd As Long, ByVal hWndInsertAfter As Long, ByVal X As Long, ByVal Y As Long, ByVal cx As Long, ByVal cy As Long, ByVal wFlags As Long) As Long

Private Const RGN_AND = 1 '交集
Private Const RGN_COPY = 5 '覆盖
Private Const RGN_OR = 2 '并集
Private Const RGN_XOR = 3 '差集
Private Const RGN_DIFF = 4

Public Type RECT
left As Long
top As Long
right As Long
bottom As Long
End Type

Public Enum ESetWindowPosStyles
SWP_SHOWWINDOW = &H40
SWP_HIDEWINDOW = &H80
SWP_FRAMECHANGED = &H20 ' The frame changed: send WM_NCCALCSIZE
SWP_NOACTIVATE = &H10
SWP_NOCOPYBITS = &H100
SWP_NOMOVE = &H2
SWP_NOOWNERZORDER = &H200 ' Don't do owner Z ordering
SWP_NOREDRAW = &H8
SWP_NOREPOSITION = SWP_NOOWNERZORDER
SWP_NOSIZE = &H1
SWP_NOZORDER = &H4
SWP_DRAWFRAME = SWP_FRAMECHANGED
HWND_TOPMOST = -1
HWND_NOTOPMOST = -2
End Enum

Public Type PointApi
X As Long
Y As Long
End Type

'constants for FillMode
Public Const ALTERNATE = 1
Public Const WINDING = 2

Private Type TRIVERTEX
X As Long
Y As Long
Red As Integer
Green As Integer
Blue As Integer
Alpha As Integer
End Type
Private Type GRADIENT_RECT
UpPerleft As Long
LowerRight As Long
End Type
Private Type GRADIENT_TRIANGLE
Vertex1 As Long
Vertex2 As Long
Vertex3 As Long
End Type
Public Const CLR_INVALID = -1

'GradientFill用到的结构
Public Enum GradientFillRectType
GRADIENT_FILL_RECT_h = 0
GRADIENT_FILL_RECT_v = 1
GRADIENT_FILL_TRIANGLE = 2
End Enum

Public Sub GradientFillTria(ByVal lngDc As Long, _
pPnt() As PointApi, _
lColor() As Long)
Dim Tvert(0 To 2) As TRIVERTEX
Dim gTRi As GRADIENT_TRIANGLE
Dim i As Integer

For i = LBound(Tvert) To UBound(Tvert)
Tvert(i).X = pPnt(i).X
Tvert(i).Y = pPnt(i).Y
setTriVertexColor Tvert(i), TranslateColor(lColor(i))
Next
gTRi.Vertex1 = 0
gTRi.Vertex2 = 1
gTRi.Vertex3 = 2

GradientFillTriangle lngDc, Tvert(LBound(Tvert)), 3, gTRi, 1, GRADIENT_FILL_TRIANGLE
End Sub

Public Sub GradientFillRect( _
ByVal lngDc As Long, _
ByRef FillRect As RECT, _
ByVal Color0 As Long, _
ByVal Color1 As Long, _
eDir As GradientFillRectType, _
Optional ByVal LinearSymmetrical As Boolean = False _
)

'参数说明 FillRect 渐变矩形区域
' Color0 ：起点颜色[对称时中心轴颜色]
' Color1 ：终点颜色[对称时边框颜色]
' eDir ：颜色渐变方向
' LinearSymmetrical:是否线性对称(纵向渐变则X轴对称，否则Y轴对称)
Dim i As Integer

Dim tTV(0 To 1) As TRIVERTEX

Dim tGR As GRADIENT_RECT
''中心渐变
If LinearSymmetrical = False Then
setTriVertexColor tTV(0), TranslateColor(Color0)
setTriVertexColor tTV(1), TranslateColor(Color1)
tTV(0).X = FillRect.left
tTV(0).Y = FillRect.top
tTV(1).X = FillRect.right
tTV(1).Y = FillRect.bottom

tGR.UpperLeft = 0
tGR.LowerRight = 1

GradientFill lngDc, tTV(0), 2, tGR, 1, eDir
'对称渐变
Else
'前半部
setTriVertexColor tTV(0), TranslateColor(Color1)
setTriVertexColor tTV(1), TranslateColor(Color0)
'横向渐变，左半部
If eDir = GRADIENT_FILL_RECT_h Then
tTV(0).X = FillRect.left
tTV(0).Y = FillRect.top
tTV(1).X = (FillRect.right + FillRect.left) / 2
tTV(1).Y = FillRect.bottom
''纵向渐变，上半部
Else
tTV(0).X = FillRect.left
tTV(0).Y = FillRect.top
tTV(1).X = FillRect.right
tTV(1).Y = (FillRect.bottom + FillRect.top) / 2
End If
tGR.UpperLeft = 0
tGR.LowerRight = 1
GradientFill lngDc, tTV(0), 2, tGR, 1, eDir

''后半部
setTriVertexColor tTV(0), TranslateColor(Color0)
setTriVertexColor tTV(1), TranslateColor(Color1)
'横向渐变，右半部
If eDir = GRADIENT_FILL_RECT_h Then
tTV(0).X = (FillRect.right + FillRect.left) / 2
tTV(0).Y = FillRect.top
tTV(1).X = FillRect.right
tTV(1).Y = FillRect.bottom
''纵向渐变，下半部
Else
tTV(0).X = FillRect.left
tTV(0).Y = (FillRect.bottom + FillRect.top) / 2
tTV(1).X = FillRect.right
tTV(1).Y = FillRect.bottom
End If
tGR.UpperLeft = 0
tGR.LowerRight = 1
GradientFill lngDc, tTV(0), 2, tGR, 1, eDir
End If
End Sub

Private Sub setTriVertexColor(tTV As TRIVERTEX, lColor As Long)
Dim lRed As Long
Dim lGreen As Long
Dim lBlue As Long

lRed = (lColor And &HFF&) * &H100&
lGreen = (lColor And &HFF00&)
lBlue = (lColor And &HFF0000) / &H100&
setTriVertexColorComponent tTV.Red, lRed
setTriVertexColorComponent tTV.Green, lGreen
setTriVertexColorComponent tTV.Blue, lBlue
End Sub
Private Sub setTriVertexColorComponent(ByRef iColor As Integer, ByVal lComponent As Long)
If (lComponent And &H8000&) = &H8000& Then
iColor = (lComponent And &H7F00&)
iColor = iColor Or &H8000
Else
iColor = lComponent
End If
End Sub

Private Function TranslateColor(ByVal oClr As OLE_COLOR, _
Optional hPal As Long = 0) As Long
' Convert Automation color to Windows color
If OleTranslateColor(oClr, hPal, TranslateColor) Then
TranslateColor = CLR_INVALID
End If
End Function

Public Sub WindowShape(hwnd As Long, _
hdc As Long, _
lBackColr As Long, _
lWidth As Integer, _
lHeight As Integer, _
lEdegeWidth As Integer)
'重塑窗体轮廓
'1.外形
Call MakeRoundCorner(hwnd, lWidth, lHeight, lEdegeWidth)

'2.外框
Call DrawEdge(hdc, lBackColr, lWidth, lHeight, lEdegeWidth)
End Sub

Private Sub MakeRoundCorner(lWnd As Long, lWidth As Integer, lHeight As Integer, intRadias As Integer)
Dim lngMainFrame As Long

lngMainFrame = CreateRoundRectRgn(0, 0, lWidth, lHeight, intRadias * 2, intRadias * 2)
SetWindowRgn lWnd, lngMainFrame, True
DeleteObject lngMainFrame
End Sub

Private Sub DrawEdge(ByVal hdc As Long, _
lBackColor As Long, _
lWidth As Integer, _
lHeight As Integer, _
Optional lEdgeWidth As Integer = 1)
Dim rctGradient As RECT
Dim Pnt(0 To 2) As PointApi '三角区域顶点
Dim VColor(0 To 2) As Long '三顶点颜色
Dim colTopLeft As Long '深色
Dim colBottomRight As Long '浅色
'四边的两色渐变
colTopLeft = VBWhite ' RGB(132, 132, 132)
colBottomRight = RGB(65, 65, 65)
'左
With rctGradient
.left = 0
.top = lEdgeWidth
.right = lEdgeWidth
.bottom = lHeight - lEdgeWidth
End With
GradientFillRect hdc, rctGradient, colTopLeft, lBackColor, GRADIENT_FILL_RECT_h, False
'上
With rctGradient
.left = lEdgeWidth
.top = 0
.right = lWidth - lEdgeWidth
.bottom = lEdgeWidth
End With
GradientFillRect hdc, rctGradient, colTopLeft, lBackColor, GRADIENT_FILL_RECT_v, False
'右
With rctGradient
.left = lWidth - lEdgeWidth
.top = lEdgeWidth
.right = lWidth
.bottom = lHeight - lEdgeWidth
End With
GradientFillRect hdc, rctGradient, lBackColor, colBottomRight, GRADIENT_FILL_RECT_h, False
'下
With rctGradient
.left = lEdgeWidth
.top = lHeight - lEdgeWidth
.right = lWidth - lEdgeWidth
.bottom = lHeight
End With
GradientFillRect hdc, rctGradient, lBackColor, colBottomRight, GRADIENT_FILL_RECT_v, False

'转角处的三色渐变
VColor(2) = lBackColor
If lEdgeWidth > 0 Then
'左上
Pnt(0).X = lEdgeWidth
Pnt(0).Y = (1 - Sqr(2)) * lEdgeWidth
Pnt(1).X = (1 - Sqr(2)) * lEdgeWidth
Pnt(1).Y = lEdgeWidth
Pnt(2).X = lEdgeWidth
Pnt(2).Y = lEdgeWidth
VColor(0) = colTopLeft
VColor(1) = colTopLeft
GradientFillTria hdc, Pnt, VColor
'左下
Pnt(0).X = (1 - Sqr(2)) * lEdgeWidth
Pnt(0).Y = lHeight - lEdgeWidth
Pnt(1).X = lEdgeWidth
Pnt(1).Y = lHeight + (Sqr(2) - 1) * lEdgeWidth
Pnt(2).X = lEdgeWidth
Pnt(2).Y = lHeight - lEdgeWidth
VColor(0) = colTopLeft
VColor(1) = colBottomRight
GradientFillTria hdc, Pnt, VColor
'右下
Pnt(0).X = lWidth - lEdgeWidth
Pnt(0).Y = lHeight + (Sqr(2) - 1) * lEdgeWidth
Pnt(1).X = lWidth + (Sqr(2) - 1) * lEdgeWidth
Pnt(1).Y = lHeight - lEdgeWidth
Pnt(2).X = lWidth - lEdgeWidth
Pnt(2).Y = lHeight - lEdgeWidth
VColor(0) = colBottomRight
VColor(1) = colBottomRight
GradientFillTria hdc, Pnt, VColor
'右上
Pnt(0).X = lWidth + (Sqr(2) - 1) * lEdgeWidth
Pnt(0).Y = lEdgeWidth
Pnt(1).X = lWidth - lEdgeWidth
Pnt(1).Y = (1 - Sqr(2)) * lEdgeWidth
Pnt(2).X = lWidth - lEdgeWidth
Pnt(2).Y = lEdgeWidth
VColor(0) = colBottomRight
VColor(1) = colTopLeft
GradientFillTria hdc, Pnt, VColor
End If

Erase Pnt
Erase VColor
End Sub

==module代码结束

本文开头提供的效果图中的窗体还使用了作者自制的“窗体标题窗控件”一个及“XP风格按钮”两个，打算视读者对本文的反应情况而决定是否也贴出来也大家共同探讨。

此乃作者第一次将自己的东西拿来贴于csdn上，希读者诸君多多提出宝贵意见与建议，以期能共同提高。