Platforms to show: All Mac Windows Linux Cross-Platform
/Images/JPEG/Quick JPEG Preview
Required plugins for this example: MBS Images Plugin
You find this example project in your Plugins Download as a Xojo project file within the examples folder: /Images/JPEG/Quick JPEG Preview
This example is the version from Sun, 9th May 2020.
Project "Quick JPEG Preview.xojo_binary_project"
Class App Inherits Application
Const kEditClear = "&Delete"
Const kFileQuit = "&Quit"
Const kFileQuitShortcut = ""
End Class
Class MainWindow Inherits Window
Control Canvas1 Inherits Canvas
ControlInstance Canvas1 Inherits Canvas
EventHandler Sub Paint(g As Graphics, areas() As REALbasic.Rect)
If pic1 <> Nil Then
Dim faktor As Double = Min( g.Height / Pic1.Height, g.Width / Pic1.Width)
// Calculate new size
Dim w As Integer = Pic1.Width * faktor
Dim h As Integer = Pic1.Height * faktor
g.DrawPicture Pic1, 0, 0, w, h, 0, 0, Pic1.Width, pic1.Height
End If
End EventHandler
End Control
Control Canvas2 Inherits Canvas
ControlInstance Canvas2 Inherits Canvas
EventHandler Sub Paint(g As Graphics, areas() As REALbasic.Rect)
If Pic2 <> Nil Then
Dim faktor As Double = Min( g.Height / Pic2.Height, g.Width / Pic2.Width)
// Calculate new size
Dim w As Integer = Pic2.Width * faktor
Dim h As Integer = Pic2.Height * faktor
g.DrawPicture Pic2, 0, 0, w, h, 0, 0, Pic2.Width, Pic2.Height
End If
End EventHandler
End Control
Control Label1 Inherits Label
ControlInstance Label1 Inherits Label
End Control
Control Label2 Inherits Label
ControlInstance Label2 Inherits Label
End Control
Control Canvas3 Inherits Canvas
ControlInstance Canvas3 Inherits Canvas
EventHandler Sub Paint(g As Graphics, areas() As REALbasic.Rect)
If Pic3 <> Nil Then
Dim faktor As Double = Min( g.Height / Pic3.Height, g.Width / Pic3.Width)
// Calculate new size
Dim w As Integer = Pic3.Width * faktor
Dim h As Integer = Pic3.Height * faktor
g.DrawPicture Pic3, 0, 0, w, h, 0, 0, Pic3.Width, Pic3.Height
End If
End EventHandler
End Control
Control Label3 Inherits Label
ControlInstance Label3 Inherits Label
End Control
Control Info1 Inherits Label
ControlInstance Info1 Inherits Label
End Control
Control Info2 Inherits Label
ControlInstance Info2 Inherits Label
End Control
Control Info3 Inherits Label
ControlInstance Info3 Inherits Label
End Control
EventHandler Sub Open()
Dim file As FolderItem = SpecialFolder.Desktop.Child("test.jpg")
If file = Nil Or Not file.Exists Then
// pick file
file = GetOpenFolderItem(FileTypes1.Jpeg)
If file = Nil Then
Quit
end if
End If
Dim m1 As Double = Microseconds
// first read header and check for thumbnail in EXIF
Dim j As New JPEGImporterMBS
j.file = file
j.ReadExifData = True
If j.ReadHeader Then
Dim m2 As Double = Microseconds
Dim thumbnailData As String = j.ExifThumbnail
Dim thumbnailPic As Picture = Nil
If thumbnailData.LenB > 0 Then
thumbnailPic = picture.FromData(thumbnailData)
End If
Dim m3 As Double = Microseconds
If thumbnailPic <> Nil Then
Pic1 = thumbnailPic
label1.Text = Str( (m3-m1) / 1000.0, "0.0")+" ms for thumbnail"
Info1.Text = Str(pic1.Width)+"x"+Str(pic1.Height)
canvas1.Invalidate
Else
label1.Text = "no thumbnail"
Info1.Text = ""
End If
// now read a scaled down image
Dim factor As Double = Min( j.Height / 300.0, j.Width / 300.0)
If factor >= 8.0 Then
j.ScaleFactor = 8
Elseif factor >= 4.0 Then
j.ScaleFactor = 4
Else
j.ScaleFactor = 2
End If
j.Import
Dim m4 As Double = Microseconds
Pic2 = j.Picture
Dim d1 As Double = m2-m1 // init time
Dim d2 As Double = m4-m3 // time for reading jpeg
If Pic2 = Nil Then
label2.Text = "no preview"
Info2.Text = ""
Else
label2.Text = Str( (d1+d2) / 1000.0, "0.0")+" ms for preview"
Info2.Text = Str(pic2.Width)+"x"+Str(pic2.Height)
canvas2.Invalidate
End If
// finally read full image
Dim m5 As Double = Microseconds
j.ScaleFactor = 0
j.ReadExifData = true
j.Import
Dim m6 As Double = Microseconds
Pic3 = j.Picture
Dim d3 As Double = m6-m5 // time for reading jpeg
If Pic3 = Nil Then
label3.Text = "no picture"
Info3.Text = ""
Else
label3.Text = Str( (d1+d3) / 1000.0, "0.0")+" ms for full picture"
Info3.Text = Str(pic3.Width)+"x"+Str(pic3.Height)
canvas3.Invalidate
End If
Title = Title+", Orientation: " + Str(j.ExifOrientation)
Else
MsgBox j.ErrorMessage
End If
End EventHandler
Property Pic1 As Picture
Property Pic2 As Picture
Property Pic3 As Picture
End Class
MenuBar MainMenuBar
MenuItem FileMenu = "&File"
MenuItem FileQuit = "#App.kFileQuit"
MenuItem EditMenu = "&Edit"
MenuItem EditUndo = "&Undo"
MenuItem EditSeparator1 = "-"
MenuItem EditCut = "Cu&t"
MenuItem EditCopy = "&Copy"
MenuItem EditPaste = "&Paste"
MenuItem EditClear = "#App.kEditClear"
MenuItem EditSeparator2 = "-"
MenuItem EditSelectAll = "Select &All"
End MenuBar
FileTypes1
Filetype image/jpeg
End FileTypes1
End Project
The items on this page are in the following plugins: MBS Images Plugin.
