Graph oddities - Help please!

[renegadeandy]

Hi all,

I am using 0-17.2 of GUISlice and using the Graph element I have drawn this graph:

**

**

The reason I think this looks strange, is the plotted line is sitting between 20 and 22. Yet the Y axis scale is between 0 and 150.

I would say the half way point of this graph is 75, so I have roughly marked this as the red area:

Here I think you can see why I think this is off. I would expect the green line to be below the half way point of the lower half of the graph - but I do not think it is, it looks like it is in the upper half of that segment. This is

The relevant code sections are:

void updateGraph(int player_count,int max_players){
    if(!set_graph_min_max){
      char max_players_str[3];
      sprintf(max_players_str,"%i",max_players);
      uint16_t max = max_players;
      gslc_ElemXGraphSetRange(&m_gui,m_pElemGraph1,0,max);
      gslc_ElemSetTxtStr(&m_gui,YAxisMax,max_players_str);
      gslc_ElemXGraphReset(&m_gui,m_pElemGraph1);
      set_graph_min_max=true;
    }
    int16_t new_val = player_count;
    gslc_ElemXGraphAdd(&m_gui,m_pElemGraph1,new_val);

  
}

That is used to add points to the graph and adjust the Y axis if needed.

The instantiation is handled by GUISliceBuilder 0.17.b40 generated code - namely:

 // Create E_ELEM_BOX1 box
  pElemRef = gslc_ElemCreateBox(&m_gui,E_ELEM_BOX1,E_PG_MAIN,(gslc_tsRect){3,75,205,78});

  // Create graph E_ELEM_GRAPH1
  pElemRef = gslc_ElemXGraphCreate(&m_gui,E_ELEM_GRAPH1,E_PG_MAIN,
    &m_sGraph1,(gslc_tsRect){4,76,202,75},E_BUILTIN5X8,(int16_t*)&m_anGraphBuf1,
        200,GSLC_COL_GREEN);
  gslc_ElemXGraphSetStyle(&m_gui,pElemRef, GSLCX_GRAPH_STYLE_DOT, 5);
  gslc_ElemSetCol(&m_gui,pElemRef,GSLC_COL_BROWN,GSLC_COL_BLACK,GSLC_COL_BLACK);
  m_pElemGraph1 = pElemRef;
  
  // Create Y_AXIS_MAX runtime modifiable text
  static char m_sDisplayText9[4] = "120";
  pElemRef = gslc_ElemCreateTxt(&m_gui,Y_AXIS_MAX,E_PG_MAIN,(gslc_tsRect){210,71,27,18},
    (char*)m_sDisplayText9,4,E_BUILTIN5X8);
  YAxisMax = pElemRef;
  
  // Create Y_AXIS_MIN runtime modifiable text
  static char m_sDisplayText10[2] = "0";
  pElemRef = gslc_ElemCreateTxt(&m_gui,Y_AXIS_MIN,E_PG_MAIN,(gslc_tsRect){212,136,19,26},
    (char*)m_sDisplayText10,2,E_BUILTIN5X8);
  YAxisMin = pElemRef;
  
  // Create X_AXIS_FIRSTTIME runtime modifiable text
  static char m_sDisplayText12[6] = "12:00";
  pElemRef = gslc_ElemCreateTxt(&m_gui,X_AXIS_FIRSTTIME,E_PG_MAIN,(gslc_tsRect){7,158,34,13},
    (char*)m_sDisplayText12,6,E_BUILTIN5X8);
  XAxisFirstTime = pElemRef;
  
  // Create X_AXIS_MIDTIME runtime modifiable text
  static char m_sDisplayText13[6] = "12:30";
  pElemRef = gslc_ElemCreateTxt(&m_gui,X_AXIS_MIDTIME,E_PG_MAIN,(gslc_tsRect){92,158,38,16},
    (char*)m_sDisplayText13,6,E_BUILTIN5X8);
  XAxisMidTime = pElemRef;
  
  // Create X_AXIS_CURRENT_TIME runtime modifiable text
  static char m_sDisplayText14[6] = "13:00";
  pElemRef = gslc_ElemCreateTxt(&m_gui,X_AXIS_CURRENT_TIME,E_PG_MAIN,(gslc_tsRect){179,156,38,16},
    (char*)m_sDisplayText14,6,E_BUILTIN5X8);
  XAxisCurrentTime = pElemRef;

I then made a test where I plot one point at 75, and the rest at 20. You can see the result of that here:

You can see the first 75 point is at the very top of the graph, not at the middle. So that suggests the total Y axis value of plotted points is wrong. Infact the 20 looks about in the right place if 75 was the max, but that could also be coincidental.

I thought I set that here:

gslc_ElemXGraphSetRange(&m_gui,m_pElemGraph1,0,max);

Where 0 is the min and max == 150 but clearly that is not doing what I think it should, or there is a bug, or I am doing something wrong!

Please help!

[Pconti31]

@renegadeandy Yes, there does seem to be a misunderstanding here.
You set the graph with a height of 75. Now GUIslice will add a frame around that of 1 pixel above and below. Giving us 73 pixels.
Now you want 0 to 150 points from what I gather. So you must map your desired values to the graph size you set up.

Example; you want to map 75 (half way up) This means 75 is to 150 as x is to 72 (0 to 73).
reduces to 150x = 75 * 72
x = (75 * 72) / 150
x = 36
which should be half way up. More or less. I'm not sure if the graph wastes some pixels at the bottom but you should get the basic idea. Change the height of your graph and you can change the mapping up or down.

By the way you can checkout my version of graph in GUIsliceSolutions:
no-flicker-graph

Paul--

[Pconti31]

@renegadeandy As for gslc_ElemXGraphSetRange() I argee that it does seem broken.

Paul--

[renegadeandy]

@Pconti31 glad you concur on the problem. Can we look at fixing it!?

[Pconti31]

@renegadeandy Yes, I intend debuging it. However, with the hoildays I don't have much time.

My suggestion is not to use gslc_ElemXGraphSetRange and instead use the formula I gave above
scaled x = (point * height of you defined rectangle - 3) / your desired max
x = (point * 72) / 150
as a work around. This should get you in the proper range more or less. Likely take some experiments.

Paul--

[renegadeandy]

That works much better. Maybe we just pop that scaling code into the add value function? And adjust all points tgo scale on setrange updates?