Implementing PaperSource.Auto

NAPS2.Lib/EtoForms/Desktop/Sidebar.cs

@@ -217,9 +217,7 @@ private void UpdateUiForProfile()
         _bitDepth.SelectedItem = profile.BitDepth;
         _resolution!.SetDpi(profile.Resolution.Dpi);
 
-        _paperSource.Items = profile.Caps?.PaperSources?.Values is [_, ..] paperSources
-            ? paperSources
-            : EnumDropDownWidget<ScanSource>.DefaultItems;
+        _paperSource.Items = ScanSourceHelper.GetCompatibleScanSources(profile, deviceDriver);
 
         var selectedSource = _paperSource.SelectedItem;
         var perSource = selectedSource switch

NAPS2.Lib/EtoForms/Ui/EditProfileForm.cs

@@ -160,9 +160,7 @@ private void UpdateUiForCaps()
     {
         _suppressChangeEvent = true;
 
-        _paperSource.Items = ScanProfile.Caps?.PaperSources?.Values is [_, ..] paperSources
-            ? paperSources
-            : EnumDropDownWidget<ScanSource>.DefaultItems;
+        _paperSource.Items = ScanSourceHelper.GetCompatibleScanSources(ScanProfile, DeviceDriver);
 
         var selectedSource = _paperSource.SelectedItem;
         var perSource = selectedSource switch
@@ -234,6 +232,7 @@ private ScanProfileCaps MapCaps(ScanCaps? caps)
             if (paperSourceCaps.SupportsFlatbed) paperSources.Add(ScanSource.Glass);
             if (paperSourceCaps.SupportsFeeder) paperSources.Add(ScanSource.Feeder);
             if (paperSourceCaps.SupportsDuplex) paperSources.Add(ScanSource.Duplex);
+            if (paperSourceCaps is { SupportsFeeder: true, SupportsFlatbed: true, CanCheckIfFeederHasPaper: true }) paperSources.Add(ScanSource.Auto);
         }
 
         return new ScanProfileCaps

NAPS2.Lib/Lang/Resources/SettingsResources.resx

@@ -222,6 +222,9 @@
   <data name="Scale_1_8" xml:space="preserve">
     <value>1:8</value>
   </data>
+  <data name="Source_Auto" xml:space="preserve">
+    <value>Auto</value>
+  </data>
   <data name="Source_Duplex" xml:space="preserve">
     <value>Duplex</value>
   </data>

NAPS2.Lib/Scan/ScanProfile.cs

@@ -171,7 +171,9 @@ public enum ScanSource
     [LocalizedDescription(typeof(SettingsResources), "Source_Feeder")]
     Feeder,
     [LocalizedDescription(typeof(SettingsResources), "Source_Duplex")]
-    Duplex
+    Duplex,
+    [LocalizedDescription(typeof(SettingsResources), "Source_Auto")]
+    Auto
 }
 
 /// <summary>
@@ -437,6 +439,8 @@ public static PaperSource ToPaperSource(this ScanSource scanSource)
                 return PaperSource.Feeder;
             case ScanSource.Duplex:
                 return PaperSource.Duplex;
+            case ScanSource.Auto:
+                return PaperSource.Auto;
             default:
                 throw new ArgumentException();
         }

NAPS2.Lib/Util/ScanSourceHelper.cs

@@ -0,0 +1,16 @@
+using NAPS2.EtoForms.Widgets;
+using NAPS2.Scan;
+
+namespace NAPS2.Util;
+
+public static class ScanSourceHelper
+{
+    public static List<ScanSource> GetCompatibleScanSources(ScanProfile profile, Driver deviceDriver)
+    {
+        if(profile.Caps?.PaperSources?.Values is not { } scanSources)
+            scanSources = [.. EnumDropDownWidget<ScanSource>.DefaultItems];
+        if (deviceDriver is not (Driver.Wia or Driver.Twain or Driver.Escl))
+            scanSources.Remove(ScanSource.Auto);
+        return scanSources;
+    }
+}

NAPS2.Sdk/Scan/Internal/Escl/EsclScanDriver.cs

@@ -173,7 +173,7 @@ public async Task Scan(ScanOptions options, CancellationToken cancelToken, IScan
             bool hasErrorDetailsExtension = caps.Naps2Extensions?.Contains("ErrorDetails") ?? false;
             bool hasShortTimeoutExtension = caps.Naps2Extensions?.Contains("ShortTimeout") ?? false;
             bool hasAnyDpiExtension = caps.Naps2Extensions?.Contains("AnyDpi") ?? false;
-            var scanSettings = GetScanSettings(options, caps, hasAnyDpiExtension);
+            var scanSettings = GetScanSettings(options, caps, hasAnyDpiExtension, status);
             Action<double>? progressCallback = hasProgressExtension ? scanEvents.PageProgress : null;
 
             if (cancelToken.IsCancellationRequested) return;
@@ -441,7 +441,7 @@ private IEnumerable<IMemoryImage> GetImagesFromRawDocument(ScanOptions options,
         }
     }
 
-    private EsclScanSettings GetScanSettings(ScanOptions options, EsclCapabilities caps, bool hasAnyDpiExtension)
+    private EsclScanSettings GetScanSettings(ScanOptions options, EsclCapabilities caps, bool hasAnyDpiExtension, EsclScannerStatus status)
     {
         if (options.PaperSource == PaperSource.Feeder && caps.AdfSimplexCaps == null)
         {
@@ -451,10 +451,16 @@ private EsclScanSettings GetScanSettings(ScanOptions options, EsclCapabilities c
         {
             throw new NoDuplexSupportException();
         }
-        if (options.PaperSource is PaperSource.Flatbed or PaperSource.Auto
-            && caps.PlatenCaps == null && caps.AdfSimplexCaps != null)
+
+        if (options.PaperSource == PaperSource.Auto)
         {
-            options.PaperSource = PaperSource.Feeder;
+            options.PaperSource = caps switch
+            {
+                { PlatenCaps: not null, AdfSimplexCaps: null } => PaperSource.Flatbed,
+                { PlatenCaps: null, AdfSimplexCaps: not null } => PaperSource.Feeder,
+                _ when status is { AdfState: not EsclAdfState.ScannerAdfEmpty } => PaperSource.Feeder,
+                _ => PaperSource.Flatbed
+            };
         }
 
         var (inputCaps, inputSource, duplex) = options.PaperSource switch

NAPS2.Sdk/Scan/Internal/Twain/TwainScanRunner.cs

@@ -336,7 +336,26 @@ private void ConfigureSource(DataSource source)
         // Paper Source
         switch (_options.PaperSource)
         {
-            case PaperSource.Auto: // Assume the data source will ignore if unsupported
+            case PaperSource.Auto:
+                if (source.Capabilities.CapFeederEnabled.IsSupported)
+                {
+                    source.Capabilities.CapFeederEnabled.SetValue(BoolType.True);
+                }
+                if (source.Capabilities.CapAutomaticSenseMedium.IsSupported)
+                {
+                    source.Capabilities.CapAutomaticSenseMedium.SetValue(BoolType.True);
+                }
+                else
+                {
+                    // Only set if CAP_AUTOMATICSENSEMEDIUM is unsupported (https://epson.com/Support/wa00954e?pg=6#:~:text=CAP_AUTOMATICSENSEMEDIUM,to%20CAP_FEEDERENABLED%20dynamically.)
+                    // CAP_FEEDERLOADED is depending on CAP_FEEDERENABLED being set to TRUE (https://epson.com/Support/wa00954e?pg=6#:~:text=TWCC_BADCAP.-,CAP_FEEDERLOADED,TRUE.,-CAP_FEEDPAGE)
+                    if (!source.Capabilities.CapFeederLoaded.IsSupported || source.Capabilities.CapFeederLoaded.GetCurrent() == BoolType.False)
+                    {
+                        source.Capabilities.CapFeederEnabled.SetValue(BoolType.False);
+                    }
+                    source.Capabilities.CapDuplexEnabled.SetValue(BoolType.False);
+                }
+                break;
             case PaperSource.Flatbed:
                 source.Capabilities.CapFeederEnabled.SetValue(BoolType.False);
                 source.Capabilities.CapDuplexEnabled.SetValue(BoolType.False);
@@ -351,20 +370,6 @@ private void ConfigureSource(DataSource source)
                 break;
         }
 
-        // TODO: Should we add an "Automatic" option in the NAPS2 GUI instead of making "Glass" = Auto?
-        // For "Auto", choose the feeder if it has paper, otherwise the flatbed.
-        if (_options.PaperSource == PaperSource.Auto)
-        {
-            if (source.Capabilities.CapAutomaticSenseMedium.IsSupported)
-            {
-                source.Capabilities.CapAutomaticSenseMedium.SetValue(BoolType.True);
-            }
-            else if (source.Capabilities.CapFeederLoaded.IsSupported &&
-                     source.Capabilities.CapFeederLoaded.GetCurrent() == BoolType.True)
-            {
-                source.Capabilities.CapFeederEnabled.SetValue(BoolType.True);
-            }
-        }
 
         // Bit Depth
         switch (_options.BitDepth)

NAPS2.Sdk/Scan/Internal/Wia/WiaScanDriver.cs

@@ -172,21 +172,18 @@ public async Task Scan(WiaVersion wiaVersion)
                 return;
             }
 
-            if (_options.PaperSource == PaperSource.Auto)
+            if (_options.PaperSource != PaperSource.Auto)
             {
-                // Default to flatbed if supported (or if both support checks fail)
-                _options.PaperSource = device.SupportsFlatbed() || !device.SupportsFeeder()
-                    ? PaperSource.Flatbed
-                    : PaperSource.Feeder;
+                if (!DoTransferWithPaperSource(device, _options.PaperSource) && !_cancelToken.IsCancellationRequested &&
+                    _options.PaperSource != PaperSource.Flatbed)
+                    throw new DeviceFeederEmptyException();
             }
-
-            using var item = GetItem(device);
-            if (item == null)
+            else
             {
-                return;
+                if (!device.SupportsFeeder() || !device.FeederReady() ||
+                    !DoTransferWithPaperSource(device, PaperSource.Feeder))
+                    DoTransferWithPaperSource(device, PaperSource.Flatbed);
             }
-
-            DoTransfer(device, item);
         }
 
         private async Task DoWia20NativeTransfer(WiaDeviceManager deviceManager, WiaDevice device)
@@ -230,7 +227,13 @@ private async Task DoWia20NativeTransfer(WiaDeviceManager deviceManager, WiaDevi
             }
         }
 
-        private void DoTransfer(WiaDevice device, WiaItem item)
+        private bool DoTransferWithPaperSource(WiaDevice device, PaperSource source)
+        {
+            using var item = GetItem(device, source);
+            return item != null && DoTransfer(device, item);
+        }
+
+        private bool DoTransfer(WiaDevice device, WiaItem item)
         {
             if (_options.PaperSource != PaperSource.Flatbed && !device.SupportsFeeder())
             {
@@ -283,7 +286,6 @@ private void DoTransfer(WiaDevice device, WiaItem item)
             transfer.Progress += (sender, args) => _scanEvents.PageProgress(args.Percent / 100.0);
             using (_cancelToken.Register(transfer.Cancel))
             {
-                _scanEvents.PageStart();
                 try
                 {
                     transfer.Download();
@@ -292,6 +294,15 @@ private void DoTransfer(WiaDevice device, WiaItem item)
                 {
                     // This error code is undocumented but seems to mean "no more pages" which can be ignored
                 }
+                catch (WiaException e) when (e.ErrorCode == 0x801901F4 && _options.PaperSource != PaperSource.Flatbed)
+                {
+                    // This error code isnt specific to wia but is returned when attempting to scan with an empty feeder
+                    // This is more reliable than WIA_DPS_DOCUMENT_HANDLING_STATUS & FEED_READY, because in some models its used to indicate a feeder is "installed" not "has pages in it"
+                    return hasAtLeastOneImage;
+                }
+
+                _scanEvents.PageStart();
+
 
                 if (device.Version == WiaVersion.Wia10 && _options.PaperSource != PaperSource.Flatbed)
                 {
@@ -308,18 +319,10 @@ private void DoTransfer(WiaDevice device, WiaItem item)
                     }
                 }
             }
-            if (scanException != null)
-            {
-                throw scanException;
-            }
-            if (!hasAtLeastOneImage && !_cancelToken.IsCancellationRequested &&
-                _options.PaperSource != PaperSource.Flatbed)
-            {
-                throw new DeviceFeederEmptyException();
-            }
+            return scanException != null ? throw scanException : hasAtLeastOneImage;
         }
 
-        private WiaItem? GetItem(WiaDevice device)
+        private WiaItem? GetItem(WiaDevice device, PaperSource source)
         {
             if (_options.UseNativeUI)
             {
@@ -369,7 +372,7 @@ private void DoTransfer(WiaDevice device, WiaItem item)
                 // The "Feeder" child may also have a pair of children (for front/back sides with duplex)
                 // https://docs.microsoft.com/en-us/windows-hardware/drivers/image/simple-duplex-capable-document-feeder
                 var items = device.GetSubItems();
-                var preferredItemName = _options.PaperSource == PaperSource.Flatbed ? "Flatbed" : "Feeder";
+                var preferredItemName = source == PaperSource.Flatbed ? "Flatbed" : "Feeder";
                 return items.FirstOrDefault(x => x.Name() == preferredItemName) ?? items.First();
             }
         }