FLUT-1020062: Enhanced Flutter Radial Gauge UG documentation

[Mugunthan-Ramalingam]

Description

Enhanced the Overview and Marker Pointer pages of the Flutter User Guide documentation for SfRadialGauge to address customer-reported gaps in marker type coverage and feature references.

https://support.syncfusion.com/agent/tickets/856905
https://support.syncfusion.com/agent/tickets/856906

Files Updated

• https://help.syncfusion.com/flutter/radial-gauge/overview
• https://help.syncfusion.com/flutter/radial-gauge/marker-pointer

Changes Made

Added

• Added cross-reference links from each Key Features bullet to its dedicated documentation page (axes, ranges, pointers, animation, annotation) in the Overview page.
• Added new Key Features bullets for Title, Animation, and Accessibility in the Overview page, with links to their dedicated pages.
• Added dedicated subsections with code examples for all seven marker types — Circle, Diamond, Inverted triangle, Rectangle, Triangle (new); Image and Text (existing) — in the Marker Pointer page.
• Added an Animation section documenting enableAnimation, animationDuration, and animationType properties with example.
• Added a Pointer interaction section documenting the onValueChanged, onValueChangeStart, onValueChangeEnd, and onValueChanging drag callbacks with a StatefulWidget example.
• Added a Custom renderer section documenting the onCreatePointerRenderer callback.
• Added asset registration note for imageUrl usage under the Image pointer section.
• Added GaugeTextStyle class reference link in the Text pointer section.

Updated

• Wrapped all 12 code samples in the Marker Pointer page with StatelessWidget class wrappers and required imports (flutter/material.dart, syncfusion_flutter_gauges/gauges.dart).
• Updated the sample link in the Overview page to point directly to lib/samples/gauge for consistency with the Linear Gauge overview.
• Standardized the marker type list in the Marker Pointer page to use MarkerType.* enum-style links with descriptions.
• Changed platform: Flutter to platform: flutter in the Marker Pointer page frontmatter for workspace consistency.

Fixed

• Fixed grammar in the Overview intro: "high-quality mobile application" → "high-quality mobile applications".
• Fixed missing article in the Pointers bullet: "Radial gauge has" → "The radial gauge has".
• Fixed "An Image" capitalization to "An image" in the Marker Pointer page.
• Fixed section heading case: "Marker Customization" → "Marker customization".
• Fixed missing period at the end of the Position customization intro sentence.
• Replaced deprecated Color.withOpacity(0.12) with Color.withValues(alpha: 0.12) in the Marker overlay customization code.

Why This Change?

• Provide coverage for every MarkerPointer API property as requested by the customer.
• Add direct links from the Overview page to the dedicated feature pages for faster navigation.
• Improve developer onboarding with complete, runnable code samples.
• Make the documentation easier to understand with consistent structure and wording.
• Ensure content and API references are accurate and up to date.

Validation

• Verified documentation flow
• Verified code samples
• Verified links
• Reviewed grammar and readability

Impact

• No API changes.
• No functional changes.
• Documentation enhancement only.

Documentation Enhancement Metrics

Category	Count
Missing Steps Added	1
New Feature Bullets Added	3
New Marker Type Subsections Added	5
New Property Sections Added	3
Code Samples Wrapped with Class/Imports	12
Technical Corrections	3
Missing Information Added	8
Grammar Improvements	5
Clarity Improvements	4
Files Modified	2

Validation report

docs-update-report.md

[SyncfusionBuild]

Build Status: INPROGRESS 🔃
Build Location: FLUT-1020062-gauge-ug

[SyncfusionBuild]

CI Status: SUCCESS ✅
Source Compilation: SUCCESS ✅
Build Location: FLUT-1020062-gauge-ug
Technical Error(s): 0
Spelling Error(s): 0
Image Alt Text Error(s): 0
Image Size Error(s): 0
Image Name Error(s): 0
Front matter Error(s): 0
File Path Error(s): 0
CodeSnippet File Path Missing Error(s): 0
Toc Anchor Tags Validation Error(s): 0
MD Tag Validation Error(s): 0

[SyncfusionBuild]

Build Status: INPROGRESS 🔃
Build Location: FLUT-1020062-gauge-ug

[SyncfusionBuild]

CI Status: SUCCESS ✅
Source Compilation: SUCCESS ✅
Build Location: FLUT-1020062-gauge-ug
Technical Error(s): 0
Spelling Error(s): 0
Image Alt Text Error(s): 0
Image Size Error(s): 0
Image Name Error(s): 0
Front matter Error(s): 0
File Path Error(s): 0
CodeSnippet File Path Missing Error(s): 0
Toc Anchor Tags Validation Error(s): 0
MD Tag Validation Error(s): 0

[sfHariHaraSudhan]

Approved.