Raindrops display picture
This example is to display in a stdpicture object, which is then displayed in the Picturebox.
Because we want to display only one picture, I don't want to use another PictureBox to store the original map, then
Draw a further PictureBox, which only uses the stdpicture object to replace the PictureBox (Source Figure)
, But Bitblt draws the word HDC for the purpose of the purpose, and the stdpicture object does not have HDC, which only
A Handle value, in this example, this handle value is a graphic hbitmap value. So we have to use
Memorydc's way, producing a MEMORYDC, putting the Bitmap graph on it, and then use Bitblt to draw. 'Demand a PictureBox (Named Picture2), a Command button)
Option expedition
Private Declare Function Bitblt Lib "GDI32" (Byval HDestdc 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 DWROP AS long) As long
Private Declare Function CreateCompatibleDC LIB "GDI32" _
(BYVAL HDC As Long) As Long
Private Declare Function SelectObject LIB "GDI32" _
(Byval HDC As Long, BYVAL HOBJECT AS Long) As long
Private Declare Function Deletedc LIB "GDI32" (Byval HDC As Long) AS Long
Const srccopy = & hcc0020
Private Picture1 AS New Stdpicture
Private submmand1_click ()
DIM I as long
DIM J AS Long
Dim Height5 As Long, Width5 As Long
DIM HMEMDC AS Long
The unit of the 'stdpicture object is himetric so you want to convert to Pixel
Height5 = scaley (Picture1.height, Vbhimetric, vbpixels)
IF Height5> Picture2.scaleHeight Then
HEIGHT5 = Picture2.scaleHeight
END IF
Width5 = scalex (Picture1.Width, Vbhimetric, VBPixels)
If Width5> Picture2.scalewidth Then
Width5 = Picture2.scaleWidth
END IF
'CREATE MEMORY DC
HMEMDC = CreateCompatibleDC (Picture2.hdc)
'Specify the Bitmap chart of Picture1 to HMEMDC
Call selectObject (HMEMDC, Picture1.Handle)
For i = height5 to 1 step -1
Call Bitblt (Picture2.hdc, 0, I, Width5, 1, _HMEMDC, 0, I, SRCCPY)
For j = i - 1 to 1 step -1
Call Bitblt (Picture2.hdc, 0, J, Width5, 1, _
HMEMDC, 0, I, SRCCOPY
NEXT J
NEXT
Call deletedc (HMEMDC)
End Sub
Private sub flow_load ()
DIM I as long
Picture2.scalemode = 3 'Sets into Pixel metrics
'Setting up to DISPLAY
SET PICTURE1 = LoadPicture ("C: / Windows / Sui.BMP")
'^^^^^^^^^^^^^^^^^^^^^^
'Loading the picture we want to show
End Sub
return
SHRINKING ICONS Down to SIZE
Abstract
You can use the windows Application Programming Interface (API)
Bitblt function to modify the size of an icon. This article explains
How to enlarge or shrink an icon.
Modifying an icon's size
You can use the windows Application Programming Interface (API)
Bitblt function to create an icon trians smaller or larger Than THE
Original icon. The Bitblt Function Copies a Memory Device Context To
ANOTHER MEMORY Device Context. (a Memory Device Context Is A Block of
Memory That Repesents a display surface, Such as an image or picture
Box Control. See Tip 31: "Creating The Windows Wallpaper Effect for A
Complete explanation of the bitblt function.)
In The Example Program Below, We First Load An icon INTO An Image
Control. Then we modify the Image Control's Height and Width
Properties So The icon Becomes 75 Percent Smaller Than ITs Original
Size. The bitblt function is kiln used to copy the icon stores
Image Control to the Picture Box Contro.
EXAMPLE Program
..........................
2. Add The Following Constant and Declare Statements to the General
Declarations Section of Form1 (Note That The Declare Statement
Must Be Typed As a Single Line Of Code): Private Declare Function Bitblt LIB "GDI" (Byval HDestDC AS Integer,
Byval x askIDEGER, BYVAL Y AS INTEGER, BYVAL NWIDTH AS INTEGER,
Byval nheight as integer, byval hsrcdc as in
Byval xsrc as integer, byval ysrc as in
BYVAL DWROP As long) AS Integer
Const srccopy = & hcc0020
3. Add A Command Button Control To Form1. Command1 IS CREATED BY
DEFAULT. SET ITS CAPTION Property to "shrink icon".
4. Add the folowing code to the click Event for Command1:
Private submmand1_click ()
DIM X as integer
DIM Y AS Integer
DIM W AS INTEGER
DIM H AS INTEGER
DIM RET AS INTEGER
Image1 = loadingPicture ("c: /vb/icons/misc/binoculr.ico")
Image1.width = 0.75 * image1.width
Image1.height = 0.75 * image1.height
Picture1.width = image1.width
Picture1.height = image1.height
X = Image1.left / Screen.twipsPerpixelx
Y = image1.top / screen.twipsperpixely
W = Picture1.Width / Screen.twipsPerpixelx
H = Picture1.height / Screen.TwipsPerpixely
Ret = Bitblt (Picture1.HDC, 0, 0, W, H, Form1.HDC, X, Y, SRCCOPY)
Picture1.refresh
End Sub
5. Add an image control to form1. Image1 is create by default. Set
ITS Stretch Property to True.
6. Add A Picture Box Control To Form1. Picture1 IS CREATED BY
DEFAULT. SET ITOREDRAW Property to True.
return
Get information on bitmap file
Add a Picture control and a CommandButton control in the Form, add a bitmap file in the Picture control, add the following code:
Private Declare Function GetObject Lib "GDI32" Alias "getObjecta" _
(Byval Hobject As Long, ByVal Ncount As long, lpobject as any) _
As long
Private Declare Function GetBitMapBits LIB "GDI32" (Byval Hbitmap As Long, _
Byval dwcount as long, lpbits as any) As long
Private Type Bitmap
BMTYPE AS Long
BMWIDTH AS long
Bmheight as long
BMWIDTHBYTES AS Long
BMPLANES AS INTEGER
BMBITSPIEL AS INTEGER
BMBITS As Long
End Type
Private submmand1_click ()
Dim Hbitmap As Long
DIM RES as long
DIM BMP as Bitmap
Dim Byteary () as Byte
DIM TOTBYTE As Long, i as long
Hbitmap = Picture1.Picture.handle
Res = getObject (HbitMap, Len (BMP), BMP) 'gets the structure of Bitmap
Totbyte = bmp.bmwidthbytes * bmp.bmheight 'How much is the total of Byte to save
Redim Byteary (Totbyte - 1)
'Saves information in Picture1 to Byteary
Res = getBitmapbits (Hbitmap, Totbyte, Byteary (0))
Debug.print "Total Bytes Copied:"; RES
Debug.print "bmp.bmbits"; bmp.bmbits
Debug.print "bmp.bmbitspixel"; bmp.bmbitspixel '
Debug.print "bmp.bmheight"; bmp.bmheight 'with prefacious image height
Debug.print "bmp.bmplanes"; bmp.bmplanes
Debug.print "bmp.bmtype"; bmp.bmtype
Debug.print "bmp.bmwidth"; bmp.bmwidth 'with a graphical width
Debug.print "bmp.bmwidthbytes"; bmp.bmwidthbytes' each scan line length of byte calculation
End Sub
return
Place a "transparent" picture
In VB, if you try to put a bird's picture on a tree on the background, you will find the tree to cover a rectangular area (ie the picture rectangle of the bird). We can transparently transparently transparently transparently transparently transparent to other parts of the picture:
We can use a WinAPI function Bitblt to make a series of bitctions to graphics to achieve this.
Function declaration:
Declare Function BitBlt Lib "gdi32" Alias "BitBlt" (ByVal hDestDC 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 DWrop As Long AS Long
Parameter explanation:
Target environment: hDestDC - target equipment environment; X-upper corner; y - top; nwidth - wide; NHEIGHT - high
Source environment: hsrcdc - source device environment; XSRC - source left corner; YSRC - source top;
DWROP - bit processing operation, such as VBSRCAND; VBSRCCopy; VBSRCERase; VBSRCINVERT, etc. (target environment or source environment can only be Picture, Form or Printer object. Each unit is pixel.)
Before processed, we need to process the bird's picture: copy one of the same graphics, set it to black (bird's background) to black (set this picture as SPIC), then do the following Processing: Where you want to copy (bird) is set to black, the remaining place setting (bird's background) is white (set this picture as Mask).
The graphic of the tree is named DPIC.
Finally, please add the following code:
R = Bitblt (DPIC.HDC, 0, 0, Spic.width, Spic.height, Mask.hdc, 0,0, Vbscrcopy)
R = Bitblt (DPIC.HDC, 0, 0, SPIC.Width, Spic.height, SPIC.HDC, 0, 0, VBScrinVert)
postscript:
1, the PaintPicture method in VB provides similar functions, but the speed is not as good as this method;
2, in this method, add some code slightly, it is not difficult to implement the display of animation.
3. This method is used in CallDLLS in the VB example.
