ON ERROR question

[TerryRitchie]

Code: (Select All)

Dim Shared erh As Integer

i = -1

pete = IMG_ColorDepth%(i)

Print pete



handler:

erh = Err

Resume Next

Function IMG_ColorDepth% (i As Long)

    '+------------------------------------------------+

    '| Returns the color depth of an image passed in. |

    '|                                                |

    '| i - the image handle                          |

    '|                                                |

    '| Returns:  0 : not an image                    |

    '|          32 : 32 bit color image              |

    '|          256 : 256 color image                |

    '|          16 : 16 color image (or text only)  |

    '|                                                |

    '| Note: this function will fail if an image      |

    '|      handle value passed in is less than -1  |

    '|      but does not belong to an actual image.  |

    '+------------------------------------------------+

    Dim c As Integer ' color counter

    Dim p As Integer ' palette counter

    On Error GoTo handler

    If _PixelSize(i) = 4 Then '                                  4 bytes per pixel?

        If erh Then i = 0: Exit Function

        IMG_ColorDepth% = 32 '                                    yes, 32 bit color image

    Else '                                                        no, 1 byte per pixel

        p = 0 '                                                  reset palette counter

        c = 0 '                                                  reset color counter

        Do '                                                      begin palette search

            If _PaletteColor(p, i) <> &HFF000000 Then c = c + 1 ' increment color counter if color found

            p = p + 1 '                                          increment palette counter

        Loop Until p = 256 '                                      leave when entire palette searched

        If c <= 16 Then '                                        16 colors or less?

            IMG_ColorDepth% = 16 '                                yes, 16 color image

        Else '                                                    no, greater than 16

            IMG_ColorDepth% = 256 '                              256 color image

        End If

    End If

End Function

So i starts in at -1, triggers the error, exits as 0.

Edit: To turn the call to handler off at some point, just place: ON ERROR GOTO 0 in the program flow.

Pete

Oh I completely understand how to implement this like you showed. The problem is the function above is a .BM library file.

My code would error out when:

'$INCLUDE:'.\lib\image\LIB_IMG_Contrast.BM'
'$INCLUDE:'.\lib\image\LIB_IMG_ColorDepth.BM'

The code outside of the function in the second .BM file will trigger an error. I could create an accompanying .BI file that contains the code outside. I'll experiment with that.