Purebasic "Enshure Format and Resize"

[Theo Gottwald]

The following procedure in Purebasic will  resize an loaded image in that way that the smaller side (x or y) will be upscaled to 512 pixels keeping the aspect ratio, if the picture size of the smaller side is smaller then 512 Pixels.
This option should be possibly deactivated using a parameter. And the resulting picture must be a JPG.

Code Select Expand

ProcedureDLL.s EnsureAndResizeJPG(FilePath.s, ResizeFlag.l = 1)
  Protected.s FileExtension, TempFilePath, ErrorMessage
  Protected.l ImageID, SaveResult, ResizeResult
  Protected.f AspectRatio, NewWidth.f, NewHeight.f
  Protected.i OriginalWidth, OriginalHeight, SmallerSide

  FilePath = Trim(FilePath)

  ; Extract the file extension
  FileExtension = LCase(ExtractFileExtension(FilePath))

  ; Check if the file exists
  If Not FileExist(FilePath)
    ErrorMessage = "Failed to load image: " + FilePath
    Goto ExitPoint
  EndIf

  ; Load the image
  ImageID = LoadImage(#PB_Any, FilePath)
  If ImageID = 0
    ErrorMessage = "Failed to load image: " + FilePath
    Goto ExitPoint
  EndIf

  ; Get original dimensions
  OriginalWidth = ImageWidth(ImageID)
  OriginalHeight = ImageHeight(ImageID)
  AspectRatio = OriginalWidth / OriginalHeight

  ; Determine the smaller side
  SmallerSide = Min(OriginalWidth, OriginalHeight)

  ; If the file is a JPG and the smaller side is larger than 511 pixels, retain the original file
  If FileExtension = "jpg" Or FileExtension = "jpeg"
    If SmallerSide > 511
      TempFilePath = FilePath
      Goto ExitPoint
    EndIf
  EndIf

  ; Resize if the smaller side is less than 512 pixels and ResizeFlag is set
  If ResizeFlag And SmallerSide < 512
    If OriginalWidth <= OriginalHeight
      NewWidth = 512
      NewHeight = NewWidth / AspectRatio
    Else
      NewHeight = 512
      NewWidth = NewHeight * AspectRatio
    EndIf
    ResizeResult = ResizeImage(ImageID, NewWidth, NewHeight, #PB_Image_Smooth)
    If ResizeResult = 0
      ErrorMessage = "Failed to resize image."
      Goto ExitPoint
    EndIf
  EndIf

  ; Generate a unique file name for the temporary JPG file
  TempFilePath = GetTempFileNameWithExtension("jpg")
  If Len(TempFilePath) = 0
    ErrorMessage = "Failed to generate a unique filename."
    Goto ExitPoint
  EndIf

  ; Save the image as a JPG
  SaveResult = SaveImage(ImageID, TempFilePath, #PB_ImagePlugin_JPEG)
  If SaveResult = 0
    ErrorMessage = "Failed to save temporary JPG file: " + TempFilePath
    Goto ExitPoint
  EndIf

  ; Free the loaded image
  FreeImage(ImageID)

  ; No errors encountered
  ErrorMessage = ""

  ExitPoint:
  If Len(ErrorMessage) > 0
    Set_Error(ErrorMessage)
    TempFilePath = ""
  EndIf

  ; Single exit point
  ProcedureReturn TempFilePath
EndProcedure