tcanvas.cpp

在linux下多媒体开发实例linux下多媒体开发

// tcanvas.cpp

// code for implementing drawing canvas

#include <iostream.h>
#include <v/vdebug.h>
#include <v/vwindow.h>

#include "tcanvas.h"
#include "tchord.h"
#include "tutils.h"

// names of notes on each string and fret
char *noteNames[numStrings][numFrets] = {
  { "E",  "F",  "F#", "G",  "G#", "A",  "A#", "B" },
  { "A" , "A#", "B",  "C",  "C#", "D",  "D#", "E" },
  { "D" , "D#", "E",  "F",  "F#", "G",  "G#", "A" },
  { "G" , "G#", "A",  "A#", "B",  "C",  "C#", "D" },
  { "B" , "C",  "C#", "D",  "D#", "E",  "F",  "F#"},
  { "E",  "F",  "F#", "G",  "G#", "A",  "A#", "B" }
};

tCanvasPane::tCanvasPane()
{
  strings[0] = strings[1] = strings[2] =
    strings[3] = strings[4] = strings[5] = 0;
  drawNotes = 1;
}

tCanvasPane::~tCanvasPane()
{
  strings[0] = strings[1] = strings[2] =
    strings[3] = strings[4] = strings[5] = 0;
  drawNotes = 1;
}

void tCanvasPane::Clear()
{
  vCanvasPane::Clear();       // clear the canvas
}

void tCanvasPane::Redraw(int px, int py, int pw, int ph)
{
  UserDebug(WindowEvents, "tCanvasPane:Redraw()\n");

  int x0, y0; // upper left corner of diagram
  int w, h;   // distance between strings and frets
  int d;      // radius of dots
  
  // scale the diagram to fit the canvas
  w = h = Min(GetHeight()/(numFrets+3), GetWidth()/(numStrings+2));
  x0 = (GetWidth() - (numStrings-1)*w)/2;
  y0 = (GetHeight() - (numFrets)*h)/2;
  d = w/2;
  
  Clear(); // start with a clean slate
  
  // draw the horizontal lines (frets)
  for (int i = 0 ; i <= numFrets ; i++) {
    DrawLine(x0, y0+i*h, x0+(numStrings-1)*w, y0+i*h);
  }
  
  // draw the vertical lines (strings)
  for (int i = 0 ; i < numStrings ; i++) {
    DrawLine(x0+i*w, y0, x0+i*w, y0+(numFrets)*h);
  }
  
  // list the fret numbers
  for (int i = 1 ; i <= numFrets ; i++) {
    char s[2];
    sprintf(s, "%1d", i);
    DrawText(x0-w/2, y0+i*h, s);
  }

  // draw the fingering
  for (int i = 0 ; i < numStrings ; i++) {
    char s[2] = "X";
    s[0] = strings[i];
    switch (strings[i]) {
    case 'X':
    case '0':
      {
	DrawText(x0+i*w-3, y0-5, s);
	break;
      }
    case '1': case '2': case '3': case '4':
    case '5': case '6': case '7': case '8':
      {
	int f = strings[i] - '0';
	DrawEllipse(x0+i*w-d/2, y0+f*h-d/2-w/2, d, d);
	break;
      }
    default:
      {
	UserDebug1(BadVals, "tCanvasPane::Redraw() bad string value `%c'", 
		   strings[i]);
      }
    }
  }
  
  // note names
  if (drawNotes) {
    for (int s = 0 ; s < numStrings ; s++) {
      int f = strings[s] - '0';
      if (f >= 0 && f <= 8) {
	DrawText(x0+s*w-3, y0+(numFrets)*h+w-3, noteNames[s][f]);
      }
    }
  }
}

void tCanvasPane::Resize(int w, int h)
{
  UserDebug(WindowEvents, "tCanvasPane:Resize()\n");
  Redraw(0, 0, 0, 0);
  vCanvasPane::Resize(w,h);
}

void tCanvasPane::DrawChord(strings_t strings, int drawNotes)
{
  UserDebug(WindowEvents, "tCanvasPane:DrawChord()\n");
  for (int i = 0 ; i < numStrings ; i++) {
    tCanvasPane::strings[i] = strings[i];
  }
  tCanvasPane::drawNotes = drawNotes;
  Redraw(0, 0, 0, 0);
}