/** 
  * Bandscope Receiver Applet 1.0.0 [FREQUENCY ANNOTATION PANEL]
  * @author Robert J Morton <robmorton@clara.net>
  * @version 13 March 2002, 20 March 2012
  * @copyright Robert J Morton (all rights reserved) */

import javax.swing.*;  // swing widgets
import java.awt.*;     // for graphics operations (GUI)

class freqfigs extends JPanel {

  private static final long 
    serialVersionUID = 213L;  // what the hell this is for, I don't know!

  private static final int
    // minimum centre frequency (in half-kHz)
    MC[] = {12000,6000,3000,1200,600,220,120},
    // number of required decimal places (including decimal point)
    DP[] = {0,0,1,1,2,2,2},
    // frequency to subtract to get first annotation (in half-kHz)
    FS[] = {10000,4000,2000,1000,400,200,100},
    // starting bias in pixels
    SB[] = {0,20,0,0,20,0,0},
    // number of annotated graduations
    NG[] = {6,5,3,3,5,3,3},
    // half-kHz/annotated graduation on frequency scale for each span choice
    FG[] = { 4000,2000,2000,1000,200,200,100},
    // pixels to jump between successive annotations
    FJ[] = {40,40,100,100,40,100,100},
    I = 5;  // text inset from beginning of text area

  private static final Font  // for Choice menus and buttons
    font = new Font("Serif",Font.PLAIN,12);

  private int 
    W = 240,  // width of frequency scale panel
    H = 20,   // height of frequency scale text area
    t,        // distance from top of panel to baseling for the text
    CF,       // entered centre frequency in half-kHz
    fs,       // selected frequency span number 0 = 10MHz ... 6 = 100kHz
    f,        // frequency of first annotation (in half-kHz)
    w,        // pixels from start of frequency scale of first annotation
    dp;       // number of decimal places needed for frequency annotations

  private String mFs;     // current mouse frequency
  private Image img;      // reference to background image for this panel
  private centrefreq cf;  // reference to centre-frequency class
  private freqspan sp;

  freqfigs(Image i, centrefreq cf, int W, int H, freqspan sp) {
    img = i;       // reference to main app class
    this.cf = cf;  // reference to centre-frequency class
    this.W = W;    // width of frequency-figures panel
    this.H = H;    // height of frequency-figures panel
    this.sp = sp;  // reference to frequency span selector instance

    // compute distance from top of panel to baseling for the text
    FontMetrics fm = getFontMetrics(font);  
    t = fm.getAscent() + (H - fm.getHeight()) /2;
  }


  void atualizar() {
    int fs = sp.getFreqSpan();
    CF = cf.getCF();  // entre frequency of currently selected band
    if(CF < MC[fs])   // make sure that the Centre Frequency CF is not less
      CF = MC[fs];    // than the minimum centre frequency for this band.

    f = CF - FS[fs];   // frequency of first annotation (in half-kHz)
    w = SB[fs]+20;     // pixels from start of freq scale of first annotation
    dp = DP[fs];       // number of decimal places for frequency annotations
    cf.setCF2(CF,dp);  // display corrected CF in the text entry field
    this.fs = fs;      // selected freq span number 0 = 10MHz ... 6 = 100kHz
    repaint();         // shedule a repaint via the event-despatching thread
  }


  public void paint(Graphics g) {  // DISPLAY FREQUENCY AT MOUSE POINTER
    g.drawImage(img, 0, 0, this);  // draw background image onto app panel
    g.setColor(Color.black);       // colour for figures
    g.setFont(font);
    for(int i=0; i < NG[fs]; i++) {  // for each frequency graduation
      convert.centreString(          // frequency annotation
        g, 
        convert.toMHz(f, dp), 
        w, 
        t           // base line for printing text
      );
      f += FG[fs];  // increment to frequency of next annotation
      w += FJ[fs];  // move to position of next annotation
    }
  }
}