画WAV的图形函数

画WAV的图形函数：
//***********************************************************************//
// //
// 画全部音频数据的波形 //
// 参数: //
// Dw_Type : 波形显示数据记录 //
// WaveMin : 波形数据的最小值 //
// WaveMax : 波形数据的最大值 //
// DrawLineColor : 画波形的颜色 //
// DrawBackColor : 画波形的背景颜色 //
// Draw : 是否画波形 //
// 返回值: 无 //
// //
//***********************************************************************//
procedure DrawAllWave(Dw_Type: TDrawWave_Type; var WaveMin, WaveMax: LongInt;
DrawLineColor, DrawBackColor: TColor; Draw: Boolean = True);
var
Buf: PChar;
i, Loop, j, k, lmax, lmin: LongInt;
Max, Min: LongInt;
X, Y: SmallInt;
DrawLoop: LongInt;
MODDrawSize: LongInt;
LoadSize: LongInt;
hFile: Integer;
begin
Application.ProcessMessages;

hFile := 0;

DrawLoop := Dw_Type.Length DIV LoadMemSize;
MODDrawSize := 0;
if (Dw_Type.Length MOD LoadMemSize) <> 0 then
begin
DrawLoop := DrawLoop + 1;
MODDrawSize := Dw_Type.Length MOD LoadMemSize;
end;

SendMessage(Application.MainForm.Handle, CM_BEGINDRAW, DrawLoop * 3, 0);

with Dw_Type.DesBitMap do
begin
Width := Dw_Type.DW;
Height := Dw_Type.DH;
Canvas.Brush.Color := DrawBackColor;
Canvas.Brush.Style := bsSolid;
Canvas.Pen.Color := DrawLineColor;
Canvas.Pen.Mode := pmCopy;
Canvas.FillRect(Rect(0, 0, Dw_Type.DW, Dw_Type.DH));
end;

if Dw_Type.Length = 0 then
begin
BitBlt(Dw_Type.DesCanvas.Handle, 0, 0, Dw_Type.DW, Dw_Type.DH,
Dw_Type.DesBitMap.Canvas.Handle, 0, 0, SRCCOPY);
Exit;
end;

case Dw_Type.FileType of //不同的方式，打开不同的文件
//移到文件音频数据开始处
CS_SAVE_PLAY: mmioseek(Dw_Type.hio, Dw_Type.Length, SEEK_END); //播方方式
CS_SAVE_RECORD: hFile := FileOpen(Dw_Type.FileName, fmOpenRead); //录音方式
end;

Max := -32768;
Min := 32767;

Try
for Loop := 1 to DrawLoop do
begin
if (MODDrawSize <> 0) AND (Loop = DrawLoop) then
LoadSize := MODDrawSize //要播放的音频数据的长度
else
LoadSize := LoadMemSize;
//开辟内存
Buf := PChar(GlobalAllocPtr(GMEM_MOVEABLE or GMEM_SHARE, LoadMemSize));

if Buf = NIL then
raise EMMIO.Create('不能分配内存！');

Try
case Dw_Type.FileType of //读音频数
CS_SAVE_PLAY: mmioRead(Dw_Type.hio, Buf, LoadSize);
CS_SAVE_RECORD: FileRead(hFile, Buf^, LoadSize);
end;

if Dw_Type.Length <= LoadMemSize then //假如小于区域长度的最大长度
begin //画区域波形
DrawPartWave(Dw_Type.Flag, Buf, Dw_Type.Length, Dw_Type.DesCanvas,
Dw_Type.DH, Dw_Type.DW, Dw_Type.DesBitMap, DrawLineColor,
DrawBackColor, Draw);
WaveMin := DrawMin;
WaveMax := DrawMax;
SendMessage(Application.MainForm.Handle, CM_DRAWPosI, DrawLoop * 3, 0);
SendMessage(Application.MainForm.Handle, CM_ENDDRAW, 0, 0);
FileClose(hFile);
Exit;
end;

for i := 0 to (LoadSize div 2 - 1) do
begin //取最大最小值
j := PCMInt(PChar(Buf)+ i * 2)^;
if j > Max then Max := j;
if j end;
Finally
GloBalFreePtr(Buf);
end;
SendMessage(Application.MainForm.Handle, CM_DRAWPosI, DrawLoop, 0);
end;
Finally
FileClose(hFile);
end;

WaveMin := Min;
WaveMax := Max;

if Not Draw then
begin
if Dw_Type.FileType = CS_SAVE_RECORD then FileClose(hFile);
SendMessage(Application.MainForm.Handle, CM_ENDDRAW, 0, 0);
Exit;
end;

Max := Max - Min;
Dw_Type.DesBitMap.Canvas.MoveTo(0, Dw_Type.DH div 2);
j := 0;
X := 0;
lmax := 0;
lmin := 32767;

hFile := 0;

case Dw_Type.FileType of //移到文件开始处
CS_SAVE_PLAY: mmioseek(Dw_Type.hio, Dw_Type.Length, SEEK_END);
CS_SAVE_RECORD: hFile := FileOpen(Dw_Type.FileName, fmOpenRead);
else
hFile := 0;
end;

Try
for Loop := 1 to DrawLoop do
begin
if (MODDrawSize <> 0) AND (Loop = DrawLoop) then
begin
//开辟内存
Buf := PChar(GlobalAllocPtr(GMEM_MOVEABLE or GMEM_SHARE, MODDrawSize));
LoadSize := MODDrawSize; //要播放的音频数据的长度
end
else begin
Buf := PChar(GlobalAllocPtr(GMEM_MOVEABLE or GMEM_SHARE, LoadMemSize));
LoadSize := LoadMemSize;
end;

if Buf = NIL then
raise EMMIO.Create('不能分配内存！');

Try
case Dw_Type.FileType of
CS_SAVE_PLAY: mmioRead(Dw_Type.hio, Buf, LoadSize);
CS_SAVE_RECORD: FileRead(hFile, Buf^, LoadSize);
end;
for i := 0 to (LoadSize div 2 - 1 ) do
begin
if j <(Dw_Type.Flag - 1) then //在同一周期内
begin
INC(j);
end
else begin
j := 0;
X := X + 1;
lmax := 0;
lmin := 32767;
end;
if Max <> 0 then
Y := Abs(PCMInt(PChar(Buf) + i * 2)^ - Min) * Dw_Type.DH div Max
else
Y := Dw_Type.DH div 2;

k := 0;
if Y > lmax then
begin
lmax := Y;
k := 1;
end;
if Y begin
lmin := Y;
k := 1;
end;
if k = 1 then
Dw_Type.DesBitMap.Canvas.LineTo(X, Y);
if X > Dw_Type.DW then break;
end;
Finally
GloBalFreePtr(Buf);
end;
SendMessage(Application.MainForm.Handle, CM_DRAWPosI, DrawLoop + Loop * 2 , 0);
end;
Finally
FileClose(hFile);
end;

//复制图像
BitBlt(Dw_Type.DesCanvas.Handle, 0, 0, Dw_Type.DW, Dw_Type.DH,
Dw_Type.DesBitMap.Canvas.Handle, 0, 0, SRCCOPY);
SendMessage(Application.MainForm.Handle, CM_ENDDRAW, 0, 0);
end;