用多媒体库 Bass.dll 播放 mp3 [12] - 绘制动态频谱 FFT
本例效果图:代码文件:
unit Unit1; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ExtCtrls, ComCtrls; type TForm1 = class(TForm) OpenDialog1: TOpenDialog; Timer1: TTimer; PaintBox1: TPaintBox; Button1: TButton; Button2: TButton; Button3: TButton; procedure FormCreate(Sender: TObject); procedure Button1Click(Sender: TObject); procedure Button2Click(Sender: TObject); procedure Button3Click(Sender: TObject); procedure FormDestroy(Sender: TObject); procedure PaintBox1Paint(Sender: TObject); procedure Timer1Timer(Sender: TObject); end; var Form1: TForm1; implementation {$R *.dfm} uses Bass; var hs: HSTREAM; {流句柄} FFTData: array[0..512] of Single; bit: TBitmap; FFTPeacks : array [0..128] of Integer; FFTFallOff : array [0..128] of Integer; procedure TForm1.FormCreate(Sender: TObject); begin Timer1.Enabled := False; Timer1.Interval := 30; bit := TBitmap.Create; PaintBox1.Align := alTop; if HiWord(BASS_GetVersion) <> BASSVERSION then MessageBox(0, '"Bass.dll" 文件版本不合适! ', nil, MB_ICONERROR); if not BASS_Init(-1, 44100, 0, 0, nil) then ShowMessage('初始化错误'); end; {打开} procedure TForm1.Button1Click(Sender: TObject); var Mp3Path: AnsiString; begin BASS_StreamFree(hs); OpenDialog1.Filter := 'Mp3 文件(*.mp3)|*.mp3|Wav 文件(*.wav)|*wav'; if OpenDialog1.Execute then Mp3Path := AnsiString(OpenDialog1.FileName); hs := BASS_StreamCreateFile(False, PAnsiChar(Mp3Path), 0, 0, 0); if hs < BASS_ERROR_ENDED then Text := '打开失败' else begin Text := string(Mp3Path); bit.Free; bit := TBitmap.Create; PaintBox1.Repaint; end; end; {播放} procedure TForm1.Button2Click(Sender: TObject); begin Timer1.Enabled := True; BASS_ChannelPlay(hs, False); end; {暂停} procedure TForm1.Button3Click(Sender: TObject); begin Timer1.Enabled := False; BASS_ChannelPause(hs); end; procedure TForm1.FormDestroy(Sender: TObject); begin BASS_Free; bit.Free; end; {刷新} procedure TForm1.PaintBox1Paint(Sender: TObject); begin PaintBox1.Canvas.StretchDraw(Bounds(0, 0, PaintBox1.Width, PaintBox1.Height), bit); end; {绘制 FFT} procedure TForm1.Timer1Timer(Sender: TObject); const w = 8; var i,di: Integer; begin if BASS_ChannelIsActive(hs) <> BASS_ACTIVE_PLAYING then Exit; BASS_ChannelGetData(hs, @FFTData, BASS_DATA_FFT1024); bit.Width := PaintBox1.Width; bit.Height := PaintBox1.Height; bit.Canvas.Brush.Color := clBlack; bit.Canvas.FillRect(Rect(0, 0, bit.Width, bit.Height)); bit.Canvas.Pen.Color := clLime; for i := 0 to Length(FFTData) - 1 do begin di := Trunc(Abs(FFTData[i]) * 500); if di > bit.Height then di := bit.Height; if di >= FFTPeacks[i] then FFTPeacks[i] := di else FFTPeacks[i] := FFTPeacks[i] - 1; if di >= FFTFallOff[i] then FFTFallOff[i] := di else FFTFallOff[i] := FFTFallOff[i] - 3; if (bit.Height - FFTPeacks[i]) > bit.Height then FFTPeacks[i] := 0; if (bit.Height - FFTFallOff[i]) > bit.Height then FFTFallOff[i] := 0; // bit.Canvas.MoveTo(i, bit.Height); // bit.Canvas.LineTo(i, bit.Height - FFTFallOff[i]); // bit.Canvas.Pixels[i, bit.Height - FFTPeacks[i]] := bit.Canvas.Pen.Color; bit.Canvas.Pen.Color := bit.Canvas.Pen.Color; bit.Canvas.MoveTo(i * (w + 1), bit.Height - FFTPeacks[i]); bit.Canvas.LineTo(i * (w + 1) + w, bit.Height - FFTPeacks[i]); bit.Canvas.Pen.Color := bit.Canvas.Pen.Color; bit.Canvas.Brush.Color := bit.Canvas.Pen.Color; bit.Canvas.Rectangle(i * (w + 1), bit.Height - FFTFallOff[i], i * (w + 1) + w, bit.Height); end; BitBlt(PaintBox1.Canvas.Handle, 0, 0, PaintBox1.Width, PaintBox1.Height, bit.Canvas.Handle, 0, 0, SRCCOPY); end; end.窗体文件:
object Form1: TForm1 Left = 222 Top = 114 Caption = 'Form1' ClientHeight = 154 ClientWidth = 476 Color = clBtnFace Font.Charset = DEFAULT_CHARSET Font.Color = clWindowText Font.Height = -11 Font.Name = 'Tahoma' Font.Style = [] OldCreateOrder = False Position = poDesigned OnCreate = FormCreate OnDestroy = FormDestroy PixelsPerInch = 96 TextHeight = 13 object PaintBox1: TPaintBox Left = 16 Top = 0 Width = 105 Height = 105 OnPaint = PaintBox1Paint end object Button1: TButton Left = 109 Top = 117 Width = 75 Height = 25 Caption = #25171#24320 TabOrder = 0 OnClick = Button1Click end object Button2: TButton Left = 206 Top = 117 Width = 75 Height = 25 Caption = #25773#25918 TabOrder = 1 OnClick = Button2Click end object Button3: TButton Left = 303 Top = 117 Width = 75 Height = 25 Caption = #26242#20572 TabOrder = 2 OnClick = Button3Click end object OpenDialog1: TOpenDialog Left = 128 Top = 24 end object Timer1: TTimer OnTimer = Timer1Timer Left = 128 Top = 72 end endposted on 2008-08-22 10:51 万一 阅读(6099) 评论(11) 编辑 收藏