Playing MP3 with multi-media library bass. dll [12]-drawing Dynamic Spectrum FFT

In this example:

Code file:

Unit unit1; interfaceuses windows, messages, sysutils, variants, classes, graphics, controls, forms, dialogs, classes, extctrls, comctrls; Type tform1 = Class (tform) opendialog1: topendialog; timer1: ttimer; Timer: timer; 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 future (Sender: tobject); end; var form1: tform1; implementation {$ R *. DFM} uses bass; var HS: hstream; {stream handle} 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. the DLL file version is not suitable! ', Nil, mb_iconerror); if not bass_init (-1, 44100, 0, 0, nil) Then showmessage ('initialization error'); end; {open} procedure tform1.button1click (Sender: tobject); var mp3path: ansistring; begin bass_streamfree (HS); opendialog1.filter: = 'mp3 file (*. MP3) | *. MP3 | WAV file (*. wav) | * WAV '; If opendialog1.execute then mp3path: = ansistring (opendialog1.filename); HS: = bass_streamcreatefile (false, pansichar (mp3path), 0, 0, 0 ); if 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.
 

Form file:

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  endend