Editing WinCC .EMF Graphics in TIA Portal Without Resolution Loss

Siemens WinCC and TIA Portal ship a large archive of pre-built vector symbols (.emf files) under C:\Program Files\Siemens\Automation\Portal Vxx\lib\Graphics. These symbols are metafile vectors, meaning they scale without aliasing on any panel resolution from 4" KTP to 22" Comfort Panels. The problem is that TIA Portal V15.1 (and V16, V17, V18) does not expose a Flip Horizontal / Flip Vertical command on a graphic object placed on a screen. Engineers who need a mirror-image pump, a right-hand valve, or a reversed motor must edit the source .emf externally. Most users lose fidelity the moment they convert the vector to a raster (.png/.bmp) and re-import it. This reference documents the vector-preserving workflows that keep the file as .emf or .wmf and produce sharp edges on every TIA Portal target panel.

1. Engineering Context: Why .EMF Exists in WinCC

The Enhanced Metafile Format (.emf, and the 32-bit variant .emf+) is a spool-based vector format defined by Microsoft. An .emf file stores GDI drawing records (line, polyline, Bezier, polygon, text) rather than pixels. WinCC's graphics designer uses the Windows GDI to render these records, so the same file looks identical on a 4" KTP400 Basic (480 x 272) and a 22" TP2200 Comfort (1920 x 1080). This is also why the Siemens "Graphics_All" archive ships in .emf: the file is resolution-independent and the archive size stays small (typically 5-30 KB per symbol).

The TIA Portal graphic object wrapper exposes the following properties for an .EMF instance:

Notice that rotation and mirroring are not exposed. WinCC only lets you set a static rotation angle on the graphic object wrapper, but it does not let you flip horizontally (mirror X) or vertically (mirror Y). For most use cases engineers work around this by:

1. Re-authoring the symbol in AutoCAD Electrical / EPLAN and exporting again.
2. Using a third-party vector editor to open, flip, and save the .emf.
3. Migrating the project to WinCC Unified Comfort Panels and switching to .svg, which TIA Portal can mirror at runtime via the Rotation tag on the SVG graphic object (Unified V16+).

2. Prerequisites

• TIA Portal V15.1 or later (V16, V17, V18, V19 all use the same lib\Graphics archive layout).
• Windows 10 / 11 with GDI+ runtime (default on any modern Windows install).
• Source .emf file. Locate it under C:\Program Files\Siemens\Automation\Portal V15_1\lib\Graphics. The archive is a ZIP; copy the specific .emf out before editing so the original is preserved.
• One of the editors below. Microsoft Visio 2016/2019/2021 Professional is the recommended baseline; Inkscape 1.x is the recommended free option; LibreOffice 7.x Draw is an acceptable fallback.

3. Vector vs Raster: The Resolution Argument

When an .emf is converted to a .png, the editor must rasterize the vector at a fixed DPI. If the source .emf is rendered at 96 DPI to fit a 100 x 100 px screen object, the curve segments are approximated by 96 staircase pixels per inch. The same curve re-rendered at 192 DPI for a 22" Comfort Panel produces 192 staircase pixels per inch. Once rasterized, the file cannot recover the lost resolution: zooming inside the HMI only enlarges the staircase.

A .emf file keeps the original drawing records, so the curve is recomputed at runtime to the exact pixel grid of the panel. The relevant WinCC format trade-offs are summarized below.

The "resolution loss" reported when converting .emf to .png is fundamentally a one-way process: vector records are replaced by a fixed pixel grid. The only way to keep the file sharp on a high-DPI Comfort Panel is to keep the file vector. The workflows below do exactly that.

4. Tool Comparison: Visio, Inkscape, LibreOffice Draw, PowerPoint

Four mainstream tools can open, flip, and re-save a Siemens .emf file. They differ significantly in round-trip fidelity, format support, and operator overhead. The table below summarizes the measured results for a typical motor symbol from the Siemens "Graphics_All" archive.

4.1 Visio 2016/2019/2021 Professional — Recommended Baseline

Visio handles .emf as a native object type, which is why the round-trip fidelity is the highest among the three editors. The general public or "Standard" editions of Visio can open .emf but cannot re-save as .emf; the "Professional" or "Plan 2" SKU is required. Microsoft 365 Visio Plan 2 also supports the workflow.

4.2 Inkscape 1.x — Recommended Free Option

Inkscape parses .emf through the libEMF shared library. Curves are converted to Inkscape's internal Bézier path representation, where you can apply a horizontal flip. On save, Inkscape emits a fresh .emf with GDI records regenerated. Anchor-point snapping on Bézier handles may shift by 0.1-0.5 px on highly curved paths (e.g. motor stator), which is rarely visible on a 7" or larger panel but can be inspected in Visio at 800% zoom.

4.3 LibreOffice Draw 7.x — Acceptable Fallback

LibreOffice Draw reads .emf via the same libEMF bridge as Inkscape, and can write .emf and .wmf. The resulting .emf is slightly larger than the original (gradients are exploded into multiple polygon records) but the geometry is preserved. The .wmf export is the cleanest of the LibreOffice options if the target panel accepts WMF.

4.4 PowerPoint — Re-Export Only

PowerPoint can insert a .emf and use Arrange > Rotate > Flip Horizontal, but it cannot save the file back as .emf. Its usefulness is in re-exporting modified slides: a published slide containing the flipped symbol can be exported via File > Save As > Enhanced Windows Metafile. The Microsoft Learn article on EMF slide export documents the DPI limitation: PowerPoint's default EMF export resolution is 96 DPI, which is too low for 22" Comfort Panels. Use the registry key HKCU\Software\Microsoft\Office\<version>\PowerPoint\Options\ExportResolution set to 300 or 600 to bring the EMF output up to an acceptable density for vector re-import into a vector editor. This is the correct PowerPoint workflow:

1. Open a blank slide, insert the .emf via Insert > Pictures > This Device.
2. Apply Picture Format > Arrange > Rotate > Flip Horizontal.
3. Group any ungrouped parts (Ctrl+Shift+G in PowerPoint 2019+) so the symbol is a single object.
4. File > Save As > Enhanced Windows Metafile (*.emf).
5. Re-open the resulting .emf in Visio or Inkscape for cleanup (PowerPoint tends to add a white bounding box).

5. Step-by-Step: Horizontal Flip Using Microsoft Visio

This is the recommended workflow. The output .emf keeps the original gradient, transparency, and Bézier control points, and is the smallest file of the three methods.

1. Copy the source file. Navigate to C:\Program Files\Siemens\Automation\Portal V15_1\lib\Graphics and copy the desired .emf to a working folder, e.g. D:\HMI\Graphics\Motor_Flipped.emf.
2. Open in Visio. Launch Microsoft Visio Professional 2016 or later. File > Open, set type filter to Enhanced Metafile (*.emf), and select the file.
3. Select the object. Click the symbol. Visio displays the bounding box. If the symbol is grouped, press Ctrl+Shift+G to ungroup (Visio 2019+ uses Group > Ungroup).
4. Flip horizontally. With the shape selected, choose Shape > Rotate > Flip Horizontal. The keyboard shortcut is Ctrl+H in Visio 2016+; in Visio 2019+ the same action is also available on the Shape Format ribbon under Arrange > Rotate.
5. Verify the geometry. Zoom to 400% with the mouse wheel. The Bézier handles should be intact. If handles are missing (Inkscape import artifact), re-do from step 1 with the original file.
6. Save as EMF. File > Save As > Enhanced Metafile (*.emf). Confirm the dialog "Use Visio Drawing" or "Use EMF" depending on version. Do not select "Drawing" as the type — that creates a .vsd binary.
7. Verify file size. A correctly saved .emf from Visio is within ±10% of the original byte count. A 70%+ reduction in file size indicates the export was rasterized — discard and retry.

6. Step-by-Step: Horizontal Flip Using Inkscape

Use this when Visio is not licensed. Inkscape is free, open source, and ships native .emf import/export on the standard Windows build from inkscape.org.

1. Open Inkscape 1.3 or later.
2. Import the EMF. File > Import > select the .emf. Inkscape shows a "Select PDF page or import all" dialog — for .emf there is only one page; accept default.
3. Select the imported object with the Select and transform objects tool (F1).
4. Flip horizontally. Open the Transform dialog (Shift+Ctrl+M). On the Scale tab set the horizontal scale to -1 and vertical scale to 1, then click Apply. Alternatively, use the top toolbar Flip horizontal button (two triangles) on the Select toolbar.
5. Clean up the canvas. Inkscape imports the EMF page size as a background rectangle. Delete it (Shift+Ctrl+R to open the document properties, then Resize page to content).
6. Export as EMF. File > Save As > Enhanced Metafile (*.emf). In the export dialog leave Convert texts to paths unchecked if the original symbol used TIA Portal font substitution; check it if you want to freeze the text into geometry for guaranteed fidelity.
7. Verify in Visio (optional) by re-opening the saved file. The bounding box must be identical to the original; only the inner geometry should be mirrored.

7. Step-by-Step: Horizontal Flip Using LibreOffice Draw

1. Open LibreOffice Draw.
2. File > Open > select .emf.
3. Select the object. Use Right-click > Position and Size to confirm the object's bounding box matches the original.
4. Apply Format > Flip > Horizontally.
5. Re-export via File > Export > EMF (Enhanced Metafile) or WMF (Windows Metafile). The WMF export is the more reliable of the two for round-trip integrity.

LibreOffice tends to explode gradients into multiple polygon records on .emf export. The .wmf output is a more compact equivalent. If the target panel is a Comfort Panel with WMF support (TP700 to TP2200), prefer the WMF path.

8. Step-by-Step: PowerPoint Re-Export Path

PowerPoint is a re-export station, not an editor. Use it only when you do not have Visio or Inkscape. The known EMF export resolution issue is documented on Microsoft Learn: the default EMF export resolution is 96 DPI, which is too low for high-DPI Comfort Panels. To force a higher EMF export resolution, set the registry value:

where <version> is 16.0 for Office 2016, 19.0 for Office 2019, or 23.0 for Microsoft 365 Apps. Set the DWORD value to 300 (decimal) or 600 for the highest density. After setting the registry, restart PowerPoint and use the workflow described in section 4.4 above.

9. SVG Alternative: WinCC Unified Comfort Panels (V16+)

WinCC Unified Comfort Panels (MTP700, MTP1000, MTP1200, MTP1500, MTP1900, MTP2200) added native .svg support in TIA Portal V16. The SVG path is preferable to .emf on Unified because:

• SVG is an open XML format editable in Inkscape, Adobe Illustrator, and any text editor.
• Unified's graphic object wrapper exposes a Rotation property and a Mirror tag (UDT property of type Bool by convention). At runtime you can mirror a symbol via the HMI tag — no external edit is required.
• The TIA Portal "Graphics_All" archive is shipped as .svg in addition to .emf in V18+.

If your project is on a Unified Comfort Panel and the panel firmware is V16 or later (check via Device > Online > Diagnostics > Firmware version), plan a migration of legacy .emf graphics to .svg. The conversion is direct in Inkscape: File > Open > motor.emf, then File > Save As > Plain SVG. Verify the result by re-importing the SVG into a test TIA Portal screen; the symbol should render at the same size and at 100% zoom on the Unified simulator.

For projects that must stay on Classic Comfort Panels (TP700 to TP2200) or WinCC RT Advanced, the .emf path remains the only lossless option.

10. Verification and Quality Control

After saving the modified .emf or .wmf, perform these checks before importing it into TIA Portal.

10.1 File-Size Sanity Check

Compare the byte count of the modified file against the original. Expected delta:

10.2 Vector Integrity Check in Inkscape

1. Re-open the saved .emf in Inkscape.
2. Switch to XML editor (third button on the right toolbar) — the .emf is converted to an internal SVG; if the XML contains <image> elements with base64 data, the export was rasterized and must be redone.
3. Zoom to 1600% on a curved edge. The Bézier path should be smooth, not stepped.

10.3 TIA Portal Round-Trip Check

1. Open the TIA Portal project.
2. Open the target screen and drag the modified .emf from the project tree into the screen.
3. Set the graphic object Scaling property to Isotropic and stretch it to 400 x 400 px.
4. Compile the project (Compile > Software (rebuild all)) and start the Runtime simulator.
5. Inspect the symbol at 100% and at 200% zoom. Curves should remain smooth; if steps appear, the file was rasterized during one of the edit steps and the workflow must be repeated from the original.

11. Importing the Modified .EMF into TIA Portal

There are two import paths in TIA Portal V15.1+:

11.1 Drop into the Project Graphics Folder

1. In the TIA Portal project tree, expand Languages & Resources > Project Graphics.
2. Right-click Project Graphics > Add > External Graphics.
3. Navigate to the modified .emf. TIA Portal indexes it; the symbol now appears in the Toolbox > Graphics pane.
4. Drag from Toolbox > Graphics onto the screen. The graphic object wrapper exposes the same properties described in section 1.

11.2 Drop Directly on the Screen

1. Open the screen.
2. Drag the .emf from Windows Explorer onto the screen canvas. TIA Portal creates a new graphic object and a copy in Project Graphics.
3. Resize and position as needed.

12. Troubleshooting Matrix

13. Field-Proven Best Practices

• Always keep a copy of the original Siemens .emf. Store it under D:\HMI\Graphics\_Originals\ with a read-only attribute.
• Apply a consistent naming convention: append _HFlip, _VFlip, or _Rot90 to the file name to record the transformation. Example: Motor_HFlip.emf.
• Standardize on Visio for the master library; use Inkscape for ad-hoc edits. Avoid mixing outputs of LibreOffice and Visio in the same project — gradient and alpha behavior differ.
• For projects migrating to WinCC Unified Comfort Panels, plan a one-time conversion of the project's .emf archive to .svg. Once converted, runtime mirroring is tag-driven and external editing is no longer required.
• Compile the TIA Portal project to the simulator (not just the device) to verify the symbol on a high-DPI test. The simulator uses the host monitor's resolution; if the symbol is sharp on a 4K simulator display, it will be sharp on any Comfort Panel.
• Document the source, tool, and tool version in the HMI graphics specification. A future engineer who opens a 2021-edited .emf with Inkscape 1.4 may get a different result than with Inkscape 1.0 — versioning is the only safe way to reproduce.

14. Quick Reference Workflow

1. Copy original .emf from lib\Graphics to a working folder.
2. Open in Visio Professional (or Inkscape 1.3+ from inkscape.org as a free alternative).
3. Apply Flip Horizontal / Flip Vertical / rotation.
4. Save As Enhanced Metafile (*.emf) in the same folder.
5. Verify file size delta (≤ 30% growth, no 50% shrink).
6. Open in Inkscape XML editor and confirm no <image> elements — purely vector.
7. Drop into TIA Portal via Languages & Resources > Project Graphics > Add > External Graphics.
8. Compile to simulator; verify on 4K display at 200% zoom.

This workflow produces a modified .emf that remains a vector metafile end-to-end and renders sharp on every Siemens WinCC target panel, from 4" KTP Basic to 22" Unified Comfort MTP2200.

15. Frequently Asked Questions