1. Software development
I want everyone to be familiar with the desktop elves, I don't want to have one? The author wanted to make a compilation, and its purpose is actually in order to get the beauty of the eyebrows, which leads out the purpose of I developed this software. If the reader has the same needs, please continue to look down, I will discuss this issue with you. Note The following sample code is described in Delphi.
2. Realization principle
In fact, the principle of desktop elves are very simple, mainly from the following steps:
1. Get the HDC of the desktop window.
The API is defined as follows:
GetDC function is used to obtain graphical device descriptors for the specified window
HDC Getdc
HWND HWND / / window handle
);
E.g:
Desktopdc: HDC; / / Define Graphical Device Description Table Handle of Desktop Window
Desktopdc: = getdc (0);
Or Desktopdc: = Getdc (getDesktopWindow ());
2. Create a memory bitmap and save the area to the desktop to save to the memory bitmap to restore the desktop when the drawing is completed. To this end, I define a function:
Procedure SaveBackground (BKCANVAS: Tcanvas; // Canvas Objects
SP_W: integer; // to save the width of the area
SP_H: integer; // to save the height of the area
Nx: integer; // To save the X coordinate of the area
Ny: integer; // to save the Y coordinate of the area
3. Transparently copy the animation object to the desktop plot area, the author used a GDIAPI function to make this feature.
Defined as follows:
Bool Transparentblt (HDC HDCDEST, / / Target Graphics Device Description Table Handle
INT nxorigindest, // Drawing rectangular X coordinate
INT NYORIGINDEST, / / Drawing Rectangular Y coordinate
INT nwidthdest, // Drawing rectangle width
INT HHEIGHTDEST, / / Drawing Rectangle Height
HDC HDCSRC, // Source Graphics Device Description Table Handle
INT nxoriginsrc, // source drawing rectangular X coordinate
INT NYORIGINSRC, // Source Picture Rectangle Y coordinate
INT nwidthsrc, // source drawing rectangle width
INT NHEIGHTSRC, / / Source Drawing Rectangle Height
UINT CRTRANSPARENT / / Set Transparent Color RGB (R, G, B)
);
note:
Windows NT: Requires 5.0 or above
Windows: Need Windows 98 or above
Other low versions are not supported.
This function is included in msimg32.dll.
The author defines a Tranbit function to dynamically call the TransparentBLT function, see Section III in specific definitions.
4. Copy the memory bitmap generated in the second step to the desktop. This frame of animation is displayed. Constantly loop 1-4, you can see continuous animation scenes.
3. Specific code
The following is a demo, debugging in Delphi5.0 Windows2000p. Create a form FORM1, put two image controls, named image1, image2, put a Timer control, name Timer1. Prepare two bitmaps, one put into image1, and put it into image2. The author used the bitmap of the following style (intercepted part), you can draw animation objects yourself, or borrow others, the author is a picture of Microsoft.
From the picture, you can see that many consecutive animation frames are included, and a picture completes an action, such as rotating a week, etc., each frame animation is exactly the same, in addition to the animated objects other pixels with a transparent color filler. Ok, you can see the specific code.
Unit unitmain;
Interface
Uses
Windows, Messages, Sysutils, Classes, Graphics, Controls, Forms, Dialogs, ExtCtrls, Stdctrls, MMSystem
Type
TFORM1 = Class (TFORM)
Timer1: TTIMER; // Explosion Timer
Image1: timage; // Store the picture of the explosion
Image2: Timage; // Picture of Storage Aircraft
Procedure Timer1Timer (Sender: TOBJECT);
Procedure formcreate (Sender: TOBJECT);
Procedure formclose (Sender: Tobject; VAR Action: Tclosection);
Private
{Private Declarations}
Desktopdc: HDC; // Description Table Scele
Stop: boolean; // Control loop variable
Expnum: integer; // Explosion Current number
Procedure evode (x: integer; y: integer); // explosion function
Procedure shipmove (x: integer; y: integer); // aircraft function
public
{Public declarations}
END;
VAR
FORM1: TFORM1;
IMPLEMENTATION
{$ R * .dfm}
/ / Save the desktop background
Procedure SaveBackground (Bkcanvas: Tcanvas;
SP_W: Integer;
SP_H: Integer;
NX: integer;
NY: integer;
VAR SC: Tcanvas;
Begin
SC: = Tcanvas.create;
Try
Sc.handle: = getdc (0);
BKCANVAS.COPYRECT (RECT (0, 0, SP_W, SP_H), SC, RECT (NX, NX SP_W, NY SP_H));
ReleaseDC (0, sc.handle);
Finally
Sc.free;
END;
END;
/ / Transparent copy image function
// Static call API function TRANSPARENTBLT
PROCEDURE TRANBIT (HDCDEST: HDC;
NxORIGINDEST: INTEGER;
NYORIGINDEST: INTEGER;
NWIDTHDEST: INTEGER;
HHEIGHTDEST: Integer;
HDCSRC: HDC;
NxORIGINSRC: Integer;
NYORIGINSRC: Integer;
NWIDTHSRC: INTEGER;
NHEIGHTSRC: Integer;
Crtransparent: uint);
VAR
LibHandle: hwnd; // Dynamic connection library handle
// Function prototype definition
Dllname: Procedure (HDCDest: HDC;
NxORIGINDEST: INTEGER;
NYORIGINDEST: INTEGER;
NWIDTHDEST: INTEGER;
HHEIGHTDEST: Integer;
HDCSRC: HDC;
NxORIGINSRC: Integer;
NYORIGINSRC: Integer;
NWIDTHSRC: INTEGER;
NHEIGHTSRC: Integer;
Crtransparent: uint; stdcall;
Begin
// The following is a routine business in the static call DLL
LibHandle: = loadingLibrary ('msimg32.dll');
IF libhandle <32 THEN
Begin
MessageBox (form1.handle, 'not found msimg32.dll', 'error', 0); exit;
END;
@Dllname: = getProcaddress (libhandle, 'transparentblt');
IF @ dllname = nil dam
Begin
MessageBox (Form1.Handle, 'Not found transparentblt in msimg32.dll', 'error', 0);
Freelibrary (librandle);
EXIT;
END;
Try
Transparentblt (HDCDest,
Nxorigindest,
NYORIGINDEST,
NWIDTHDEST,
Hheightdest,
HDCSRC,
Nxoriginsrc,
NYORIGINSRC,
NWIDTHSRC,
NHEIGHTSRC,
Crtransparent);
Finally
Freelibrary (librandle);
END;
END;
// Explosion function
// Explosion occurred at the X, Y coordinate of the desktop
Procedure TFORM1.EXPLODE (X: Integer; Y: Integer);
VAR
Bitmapb: Tbitmap; // Save the memory bitmap of the desktop specified area
W: integer; // a frame of one frame
H: INTEGER; // One frame of animation
i: integer;
J: integer;
Begin
Bitmapb: = Tbitmap.create;
Try
// Animation bitmap is 4 * 5 = 20 frames
W: = image1.width div 4; // calculate the width of each frame
H: = image1.height div 5; // calculate the height of each frame
// Initialization of the size of the map
Bitmapb.height: = h;
Bitmapb.width: = W;
/ / Save bitmaps in the specified area on your desktop
// Note that since the explosion is done in the same location, just save the explosion area once.
SaveBackground (Bitmapb.canvas, W, H, X, Y);
For i: = 0 to 4 do
Begin
For j: = 0 to 3 do
Begin
// Painted the corresponding frame on the desktop
Tranbit (Desktopdc, X, Y, W, H,
Image1.canvas.handle, J * W, I * H, W, H, RGB (208, 2, 178);
Sleep (20); // Show speed too fast, pause 20 milliseconds
// Restore the desktop
Bitblt (Desktopdc, X, Y, W, H, Bitmapb.canvas.Handle, 0, 0, SRCCopy);
END;
END;
Finally
Bitmapb.free;
END;
END;
// Aircraft flight function
// Parameter X, Y Specifies the destination of the aircraft flight
Procedure TFORM1.SHIPMOVE (X: Integer; Y: Integer);
VAR
W: integer;
H: integer;
i: integer;
J: integer;
K: integer;
l: integer;
Bitmapb: Tbitmap;
Begin
Randomize ();
Bitmapb: = Tbitmap.create;
Try
// Animation bitmap is 4 * 16-3 frame empty frame = 61 frames
W: = image2.width Div 4;
H: = image2.height Div 16;
Bitmapb.height: = h;
Bitmapb.width: = W;
K: = 0;
L: = 0;
While Not Stop DO
For i: = 0 to 15 DOFOR J: = 0 to 3 DO
Begin
IF (i = 15) and (i> 0) Then Break; // If you are empty frame, you will not draw it.
/ / Save bitmaps in the specified area on your desktop
// Note that since the flight is done in different locations, it is necessary to save the desktop area that will be drawn.
SaveBackground (Bitmapb.canvas, W, H, K, L);
Tranbit (Desktopdc, K, L, W, H, Image2.canvas.handle, J * W, I * H, W, H, RGB (208, 2, 178));
Sleep (10);
Bitblt (Desktopdc, K, L, W, H, Bitmapb.canvas.Handle, 0, 0, Srcopy);
IF (k IF (l if Timer1.enabled = False Then IF (k> x-10) THEN / / stop flying in the destination, and detonate bombs Begin STOP: = True; Timer1.enabled: = true; // bomb detonator END; END; Finally Bitmapb.free; END; END; Procedure TFORM1.TIMER1TIMER (Sender: TOBJECT); VAR X, Y: integer; Begin IF (expnum = 0) THEN Begin Explode (Screen.Width Div 2-20, Screen.height Div 2-20); SNDPLAYSOUND ('Explosion.wav', SND_NOSTOP); ExpNum: = evnum 1; end Else if Expnum <10 THEN / / Explosion up to 10 times Begin // Generate a random position x: = random (screen.width-100); Y: = random (screen.height-100); Explode (x, y); // explosion SNDPLAYSOUND ('Explosion.wav', SND_NOSTOP); // Playing Explosion Sound ExpNum: = evnum 1; end Else Begin STOP: = True; Timer1.enabled: = FALSE; CLOSE (); END; END; Procedure TFORM1.FormCreate (Sender: TOBJECT); Begin Desktopdc: = getdc (0); ExtractFilePath (Application.exename); STOP: = false; ExpNum: = 0; // The aircraft starts to fly, the destination is the center of the screen Self.shipmove (Screen.Width Div 2, Screen.height Div 2); END; Procedure TFORM1.FORMCLOSE (Sender: TpoBject; VAR Action: Tclosection); Begin STOP: = True; Timer1.enabled: = FALSE; ReleaseDC (0, Desktopdc); END; End. 4 Conclusion As we hope, a aircraft flew into the desktop, slowly approaching the center of the screen, exploding when it arrived at the destination, and led a series of explosions. The procedure has completed our hopes smoothly, but there are still many shortcomings, and it is best to use DirectX to complete the animation, so that the effect may be better. If you are interested in it, send me E_mail to me, let us discuss. (E_mail: codehunter@sohu.com) 3/29/2001 4:18:19 PM
