/** 
  * Bandscope Receiver Applet 1.0.0 [FREQUENCY ANNOTATION PANEL]
  * @author Robert J Morton <robmorton@clara.net> YE572246C
  * @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 {  /*

  MC[]: minimum centre frequency (in half-kHz)
  DP[]: number of required decimal places (including decimal point)
  FS[]: frequency to subtract to get first annotation (in half-kHz)
  SB[]: starting bias in pixels
  NG[]: number of annotated graduations
  FG[]: half-kHz per graduation of frequency scale for each span choice
  FJ[]: pixels to jump between successive annotations */

  private static final int
    MC[] = {12000, 6000, 3000, 1200, 600, 220, 120 },
    DP[] = {    0,    0,    1,    1,   2,   2,   2 },
    FS[] = {10000, 4000, 2000, 1000, 400, 200, 100 },
    SB[] = {    0,   20,    0,    0,  20,   0,   0 },
    NG[] = {    6,    5,    3,    3,   5,   3,   3 },
    FG[] = { 4000, 2000, 2000, 1000, 200, 200, 100 },
    FJ[] = {   40,   40,  100,  100,  40, 100, 100 },

    I = 5;  // text inset from beginning of text area

  // Font for Choice Menus and buttons.
  private static final Font 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 required 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 applet 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 instance of frequency span selector

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


  void atualizar() {

    /* Get the frequency span and centre frequency of the currently
    selected band and ensure that the Centre Frequency CF is not
    less than the minimum centre frequency for this band. */

    int x = MC[fs], fs = sp.getFreqSpan(); 
    if((CF = cf.getCF()) < x) CF = x;

    f = CF - FS[fs];  // frequency of first annotation (in half-kHz)

    // pixels from start of frequency scale of first annotation
    w = SB[fs] + 20;

    // number of decimal places required for frequency annotations
    dp = DP[fs];

    cf.setCF2(CF, dp);  // display corrected CF in the text entry field

    this.fs = fs;  // selected frequency span number 0 = 10MHz to 6 = 100kHz
    repaint();     // shedule a repaint via the event-despatching thread
  }


  public void paint(Graphics g) {  // DISPLAY FREQUENCY AT MOUSE POINTER

    // draw the background image onto the applet canvas
    g.drawImage(img, 0, 0, this);

    // colour and font for figures
    g.setColor(Color.black); g.setFont(font);

    /* For each frequency graduation, get the frequency annotation base
    line for printing text, then afterwards increment to the frequency
    of, and move to position of, the next annotation. */

    for(int i = 0; i < NG[fs]; i++) {
      convert.centreString(g, convert.toMHz(f, dp), w, t);
      f += FG[fs]; w += FJ[fs];
    }
  }
}