Make the library fully cross-platform: remove GDI+ (System.Drawing.Common), CI on Linux by davidnmbond · Pull Request #6 · panoramicdata/PanoramicData.EPPlus

davidnmbond · 2026-10-12T15:28:22Z

Summary

Removes every dependency on the GDI+ parts of System.Drawing so the library and its whole test suite run on Linux, and puts CI back on ubuntu-latest. System.Drawing.Color/Point/Size (plain structs in the shared framework) are still used.

System.Drawing.Common package reference removed; all Image/Bitmap/Graphics/Font/Imaging use and all [SupportedOSPlatform("windows")] / OperatingSystem checks removed.
Pictures: new managed ImageHeaderReader reads width/height/DPI from PNG, JPEG, GIF, BMP, TIFF, EMF, WMF headers and sniffs the content type. File bytes are stored verbatim (no re-encoding to JPEG). Loading a picture from a package no longer throws off Windows.
Autofit: TextMeasurer uses SkiaSharp (MIT) + SkiaSharp.NativeAssets.Linux. No ImageSharp. If the native library cannot load, AutoFitColumns leaves widths unchanged (as the old GDI-missing path did) and now restores DoAdjustDrawings.
NBGV 10.1 -> 11.0; breaking changes in PackageReleaseNotes.

Breaking API changes

Removed:

ExcelDrawings.AddPicture(string, Image) and (string, Image, Uri)
ExcelPicture.Image, ExcelPicture.ImageFormat
ExcelBackgroundImage.Image
ExcelVmlDrawingPicture.Image
ExcelHeaderFooterText.InsertPicture(Image, PictureAlignment)
ExcelFont.SetFromFont(Font), ExcelTextFont.SetFromFont(Font), ExcelFontXml.SetFromFont(Font)

Added / changed:

ExcelDrawings.AddPicture(string, byte[]), (string, byte[], Uri), (string, Stream), (string, Stream, Uri); the FileInfo overloads remain (read bytes)
ExcelPicture.ImageBytes (get/set), ExcelPicture.ContentType now public
ExcelBackgroundImage.ImageBytes, SetFromStream; SetFromFile kept
ExcelVmlDrawingPicture.ImageBytes
ExcelHeaderFooterText.InsertPicture(byte[], ...), InsertPicture(Stream, ...); FileInfo overload kept
Autofit widths may differ slightly from GDI+ (Skia measures without GDI's padding; a missing font falls back to the platform default).

Tests

Deleted: none.
Ported: SetFromFont(new Font(..)) call sites to property setters (DrawingTest, WorkSheetTests, SampleApp); Resources.Test1 is now byte[]; SetBackground uses ImageBytes; Issue100/Issue10 (ignored) use bytes.
AddPictureFromBytes_RoundTripsThroughASavedPackage: platform branch removed; now reopens and reads the picture back via ImageBytes.
New: header-reader tests (PNG/JPEG/GIF/BMP/truncated), AddPicture(byte[]) auto-size, Stream and FileInfo overloads.
SampleApp: removed the Windows-only shell icon extraction. EPPlusExcelCalculationSample (WinForms, not in the solution) is untouched.
Test-bug fixes (root causes of the old CI exclusions):
- DateFunctionsWorkWithDifferentCultureDateFormats_*: exception on the worker thread crashed the host; now captured and asserted on the test thread, and the culture is created without user overrides.
- RunDrawingTests / SetBackground: TestBase extracted clipart using the wrong resource-name prefix; fixed. Also path separators (\) in TestBase and several tests replaced with Path.Combine.
- RunWorksheetTests: assertions compared against 15-digit literals; use the full round-trip values.
- Issuer246: assertion arguments/expected text depended on OS culture data; now computed from the sv-SE long date.
- Issue333: sets sv-SE explicitly (the format is the culture short date).
- New TestAssemblySetup fixes the suite to en-US.
All --filter exclusions removed from CI (--blame-hang-timeout 5m and the Codacy upload are kept). Locally on Windows the entire suite passes with no filter: 1176 passed, 214 skipped (pre-existing [Ignore]s).

CI

build job is ubuntu-latest; no Windows runner anywhere.

🤖 Generated with Claude Code

…p text measurement Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

…; add header reader tests Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

…d precision test bugs; release notes, NBGV 11.0 Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

codacy-production · 2026-10-12T15:29:35Z

Not up to standards ⛔

🔴 Issues 2 high · 4 medium · 1 minor

Alerts:
⚠ 7 issues (≤ 0 issues of at least minor severity)

Results:
7 new issues

Category Results

BestPractice 1 high

ErrorProne 1 high

CodeStyle 1 minor

Complexity 4 medium

View in Codacy

🟢 Metrics 54 complexity · -3 duplication

Metric Results

Complexity 54

Duplication -3

View in Codacy

🟢 Coverage 73.40% diff coverage · +9.61% coverage variation

Metric Results

Coverage variation ✅ +9.61% coverage variation (-1.00%)

Diff coverage ✅ 73.40% diff coverage

View coverage diff in Codacy

Coverage variation details

Coverable lines Covered lines Coverage

Common ancestor commit (85c2320) 47155 25865 54.85%

Head commit (bce00dd) 47272 (+117) 30473 (+4608) 64.46% (+9.61%)

Coverage variation is the difference between the coverage for the head and common ancestor commits of the pull request branch: <coverage of head commit> - <coverage of common ancestor commit>

Diff coverage details

Coverable lines Covered lines Diff coverage

Pull request (#6) 406 298 73.40%

Diff coverage is the percentage of lines that are covered by tests out of the coverable lines that the pull request added or modified: <covered lines added or modified>/<coverable lines added or modified> * 100%

AI Reviewer: first review requested successfully. AI can make mistakes. Always validate suggestions.

_{TIP This summary will be updated as you push new changes.}

codacy-production

Pull Request Overview

⚠️ Resolve issues before merging

The Linux CI command now runs previously excluded tests, including documented failures and host-crashing culture tests, so the pipeline may fail for reasons unrelated to this change. The culture test also leaks state when assertions fail.

Image-header parsing remains a high-risk, uncovered area: TIFF/EMF/WMF scenarios and malformed-offset handling are not sufficiently tested. The autofit fallback also leaves DoAdjustDrawings unrestored on an early return.

About this PR

Verify that active tests use platform-neutral temporary paths and that CI explicitly runs the complete unfiltered suite on ubuntu-latest.

Test suggestions

Prompt proposal for missing tests

Consider implementing these tests if applicable:
1. Validate TIFF, EMF, and WMF dimensions, resolution, and content types
2. Exercise background-image byte storage and replacement/removal
3. Exercise header/footer and VML picture byte APIs
4. Verify autofit with SkiaSharp and the unavailable-native-library fallback
5. Verify autofit restores DoAdjustDrawings on every exit path
6. Add malformed-offset and unsupported-TIFF-field tests for ImageHeaderReader

_{TIP Improve review quality by adding custom instructions}
_{TIP How was this review? Give us feedback}

codacy-production · 2026-10-12T15:31:08Z

+	private static (int, int, float, float) ReadTiff(ReadOnlySpan<byte> b)
+	{
+		var little = b[0] == 0x49;
+		ushort U16(ReadOnlySpan<byte> s, int o) => little ? BinaryPrimitives.ReadUInt16LittleEndian(s[o..]) : BinaryPrimitives.ReadUInt16BigEndian(s[o..]);
+		uint U32(ReadOnlySpan<byte> s, int o) => little ? BinaryPrimitives.ReadUInt32LittleEndian(s[o..]) : BinaryPrimitives.ReadUInt32BigEndian(s[o..]);
+		double Value(ReadOnlySpan<byte> s, int entry)
+		{
+			var type = U16(s, entry + 2);
+			switch (type)
+			{
+				case 3:
+					return U16(s, entry + 8);   // SHORT
+				case 4:
+					return U32(s, entry + 8);   // LONG
+				case 5:                         // RATIONAL
+					var at = (int)U32(s, entry + 8);
+					return (double)U32(s, at) / Math.Max(1U, U32(s, at + 4));
+				default:
+					return 0;
+			}
+		}
+
+		var ifd = (int)U32(b, 4);
+		var count = U16(b, ifd);
+		double width = 0, height = 0, xres = 0, yres = 0;
+		var unit = 2;
+		for (var i = 0; i < count; i++)
+		{
+			var entry = ifd + 2 + (i * 12);
+			switch (U16(b, entry))
+			{
+				case 256:
+					width = Value(b, entry);
+					break;
+				case 257:
+					height = Value(b, entry);
+					break;
+				case 282:
+					xres = Value(b, entry);
+					break;
+				case 283:
+					yres = Value(b, entry);
+					break;
+				case 296:
+					unit = (int)Value(b, entry);
+					break;
+			}
+		}
+
+		var scale = unit == 3 ? 2.54 : 1;
+		return ((int)width, (int)height, (float)(xres * scale), (float)(yres * scale));


_{🔴 HIGH RISK}

Add focused tests for TIFF, EMF, and WMF dimensions and DPI, truncated and malformed offsets, and unsupported TIFF field types. Add an explicit TIFF switch default that deliberately ignores optional fields or rejects unsupported required data with InvalidDataException.

See Coverage in Codacy
See Issue in Codacy

codacy-production · 2026-10-12T15:31:08Z

        dotnet test PanoramicData.EPPlus.Test/PanoramicData.EPPlus.Test.csproj
        --configuration Release --no-build
        --collect "Code Coverage;Format=Cobertura" --results-directory ./coverage
        --blame-hang-timeout 5m


_{🔴 HIGH RISK}

Retain or replace exclusions for known failing tests, or fix those tests before removing the filter; otherwise this command re-enables documented failures in the Linux CI run.

codacy-production · 2026-10-12T15:31:08Z

-			{
-				throw new Exception("Name already exists in the drawings collection");
-			}
+			throw new Exception("AddPicture: ImageFile can't be null");


_{🔴 HIGH RISK}

Suggestion: Use ArgumentNullException for a null FileInfo argument.

See Issue in Codacy

codacy-production · 2026-10-12T15:31:08Z

@@ -165,15 +175,15 @@ public ExcelVmlDrawingPicture InsertPicture(FileInfo PictureFile, PictureAlignme

 		var contentType = ExcelPicture.GetContentType(PictureFile.Extension);
 		var uriPic = XmlHelper.GetNewUri(_ws._package.Package, "/xl/media/" + PictureFile.Name[..^PictureFile.Extension.Length] + "{0}" + PictureFile.Extension);
-		var imgBytes = ImageCompat.GetImageAsByteArray(Picture);

 		var ii = _ws.Workbook._package.AddImage(imgBytes, uriPic, contentType);

-		return AddImage(Picture, id, ii);
+		return AddImage(header, id, ii);


_{🟡 MEDIUM RISK}

Add cross-platform tests for InsertPicture(byte[]), InsertPicture(Stream), and InsertPicture(FileInfo), including dimensions, invalid/truncated data, duplicate-section validation, and verification that stored package bytes remain unchanged.

See Coverage in Codacy

codacy-production · 2026-10-12T15:31:08Z

+			//No usable font engine (native SkiaSharp library missing): leave the widths as they are.
+			_worksheet.Drawings.AdjustWidth(drawWidths);
+			_worksheet._package.DoAdjustDrawings = doAdjust;
 			return;


_{🟡 MEDIUM RISK}

Restore DoAdjustDrawings before returning from this path, as in the normal completion path.

codacy-production · 2026-10-12T15:31:08Z

+		System.Threading.Thread.CurrentThread.CurrentCulture = new CultureInfo("sv-SE", false);
+		var sv = new CultureInfo("sv-SE", false);
+		Assert.AreEqual(new DateTime(2018, 12, 31).ToString("D", sv), ws.Cells["A1"].Text);
 		Assert.AreEqual(ws.GetValue<DateTime>(1, 1), new DateTime(2018, 12, 31));
 		System.Threading.Thread.CurrentThread.CurrentCulture = pCulture;


_{🟡 MEDIUM RISK}

Restore the previous culture in a finally block surrounding the assertions.

codacy-production · 2026-10-12T15:31:08Z

+		Create(node, imageBytes, contentType, "/xl/media/image{0}" + GetExtension(contentType), widthPixels, heightPixels, ImageHeaderInfo.DefaultDpi, ImageHeaderInfo.DefaultDpi, hyperlink);
+	}
+
+	private void Create(XmlNode node, byte[] imageBytes, string contentType, string uriTemplate, int widthPixels, int heightPixels, float horizontalDpi, float verticalDpi, Uri hyperlink)


_{🟡 MEDIUM RISK}

Suggestion: Consider introducing an image metadata/options object to replace the positional parameter list.

See Issue in Codacy

davidnmbond and others added 4 commits October 12, 2026 15:16

refactor: remove System.Drawing.Common; pictures from bytes, SkiaShar…

7e9ccac

…p text measurement Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

test: port picture, background and font tests to bytes and properties…

f67e544

…; add header reader tests Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

chore: remove Windows-only icon extraction and Font usage from SampleApp

bc88274

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

ci: back to ubuntu-latest, drop test exclusions; fix culture, path an…

bce00dd

…d precision test bugs; release notes, NBGV 11.0 Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

codacy-production Bot reviewed Oct 12, 2026

View reviewed changes

davidnmbond merged commit 22a7e64 into main Oct 12, 2026
6 of 7 checks passed

davidnmbond mentioned this pull request Oct 12, 2026

Address the Codacy findings on #6 (TIFF/EMF/WMF tests, input validation) #7

Merged

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Make the library fully cross-platform: remove GDI+ (System.Drawing.Common), CI on Linux - #6

Make the library fully cross-platform: remove GDI+ (System.Drawing.Common), CI on Linux#6
davidnmbond merged 4 commits into
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feature/cross-platform-drawing

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davidnmbond commented Oct 12, 2026

Summary

Breaking API changes

Tests

CI

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Not up to standards ⛔

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Pull Request Overview

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codacy-production Bot commented Oct 12, 2026 •

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