Arabic Text Components Render with ~36% Excess Height When Using Noto Naskh Arabic Font

[noob]

Arabic Text Components (Noto Naskh Arabic Font) Render with ~36% Excess Height on AutoGrow

Product: Stimulsoft.Reports.Blazor
Version: 2026.2.2
Severity: High

Description:

Text components using the Noto Naskh Arabic font (NotoNaskhArabic-Regular.ttf / NotoNaskhArabic-Bold.ttf) render with approximately 36% excess height when AutoGrow = true and the component content is populated at runtime. The excess space appears as blank whitespace below the Arabic text within the component bounds.

Steps to Reproduce:

1. Create a report with a StiText component.
2. Set the font to Noto Naskh Arabic, size 12pt.
3. Bind the component to a data field containing multi-word Arabic text (e.g. a sentence of 10–15 Arabic words).
4. Enable AutoGrow = true on the component.
5. Render the report using Stimulsoft.Reports.Blazor.
6. Observe the rendered component height in the viewer vs. the actual text content height in the browser.

Expected Result:

The rendered component height fits the Arabic text content with no excess blank space — consistent with how the same text renders in the browser using the same font and size.

Actual Result:

The rendered component height is approximately 1.357× (35.7%) taller than the actual text content height.

Example measurement (same component, same font, same data):

Actual text height in browser: 529px
Stimulsoft rendered component height: 718px
Ratio: 718 ÷ 529 = 1.357

Root Cause Analysis:

The Stimulsoft text measurement engine appears to apply GSUB Arabic ligature/contextual shaping when calculating string width for word-wrap purposes. This joins Arabic characters into their contextual connected forms before measuring, producing line widths that are ~1.36× wider than what the browser renders for the same text using the same font.

This width discrepancy causes the internal word-wrap algorithm to produce ~1.36× more line breaks than are actually needed, and therefore AutoGrow expands the component to ~1.36× the correct height.

This issue is specific to:

• Arabic script fonts — confirmed with Noto Naskh Arabic (Regular and Bold)
• Text components with AutoGrow = true and multi-word Arabic content populated at runtime

Font Information:

Code: Select all

Family:      Noto Naskh Arabic
File:        NotoNaskhArabic-Regular.ttf
UPM:         1000
WinAscent:   1405
WinDescent:  351
TypoAscent:  1405
TypoDescent: -351
yMax:        1405
yMin:        -590

Environment:

Code: Select all

.NET Version:       10.0
Stimulsoft Version: 2026.2.2

NotoNaskhArabicFontTest.mrt

(267.86 KiB) Downloaded 3 times

[noob]

Updated the post.

[Max Shamanov]

Hello,

Could you please clarify what you mean by ‘Auto Grow’: ‘Can Grow’ or ‘Grow to Height’?

Thank you.

[noob]

Hi,

i mean 'Can Grow' = true

[noob]

please check the attached screenshot for more clarifications.

Screenshot5.png (531.87 KiB) Viewed 100 times

[Max Shamanov]

Hello,

We would need more time to get an answer for you.
We will let you know as soon as we have any results.

Thank you.
#20239