如何修复C++中希伯来文（RTL）文本显示反向的问题？

Hey Daniel,

You’ve already got the DLL set up to support the Hebrew 1255 charset, but the reverse display issue happens because just setting the charset isn’t enough to handle right-to-left (RTL) text layout rules—you also need to explicitly enable RTL layout and bidirectional (BiDi) text support for your UI elements or rendering logic.

Here’s how to fix this step by step:

1. Enable RTL Layout for Your Chat Control #

If you’re using standard Windows controls (like Edit or RichEdit for chat input/display), you need to set the WS_EX_LAYOUTRTL extended window style to force the control to use RTL layout:

// Replace hWnd with your actual chat control window handle
LONG exStyle = GetWindowLongPtr(hWnd, GWL_EXSTYLE);
exStyle |= WS_EX_LAYOUTRTL;
SetWindowLongPtr(hWnd, GWL_EXSTYLE, exStyle);

// Refresh the control to apply the new style
InvalidateRect(hWnd, NULL, TRUE);
UpdateWindow(hWnd);

For edit controls, adding the ES_RIGHT style can also help align text to the right, though WS_EX_LAYOUTRTL should handle the overall direction of content flow.

2. Handle Bidirectional Text Reordering #

Older systems or custom rendering engines might not automatically adjust BiDi text order. In that case, use Windows’ built-in BiDi functions like GetCharacterPlacement to reorder the characters correctly for display:

// Example: Convert logical Hebrew string to display-ready order
WCHAR logicalHebrew[] = L"שלום"; // Your input string (logical typing order)
WCHAR displayHebrew[256] = {0};

GCP_RESULTS gcpResults = {0};
gcpResults.lStructSize = sizeof(GCP_RESULTS);
gcpResults.lpOutString = displayHebrew;
gcpResults.nOutString = sizeof(displayHebrew) / sizeof(WCHAR);

// Flags to enable reordering for RTL text
DWORD gcpFlags = GCP_REORDER | GCP_USEKERNING;

GetCharacterPlacementW(GetDC(hWnd), logicalHebrew, wcslen(logicalHebrew), 0, &gcpResults, gcpFlags);
// Now displayHebrew has the correct RTL visual order

3. Adjust Text Rendering Flags (For Custom Drawing) #

If you’re drawing text manually (not using standard controls), make sure your rendering functions respect RTL direction. Use SetTextAlign to set RTL reading mode:

HDC hdc = GetDC(hWnd);
// Set text alignment to right-to-left reading mode
SetTextAlign(hdc, TA_RIGHT | TA_RTLREADING);
// Draw the text starting from the right edge of your target area
TextOutW(hdc, rightXPos, yPos, hebrewText, wcslen(hebrewText));
ReleaseDC(hWnd, hdc);

Quick Notes #

• Keep in mind: Hebrew text is stored in logical order (the order you type it), but needs to be displayed in visual order (right-to-left). Most modern controls handle this automatically, but custom or outdated code might skip this critical reordering step.
• Double-check your input handling logic to ensure it isn’t manually reversing characters before storing or displaying them.

内容的提问来源于stack exchange，提问作者universalmu