12 Text and Display Settings to Test in Mobile Apps

Test the largest text sizes (iOS Dynamic Type including accessibility sizes, and Android font scaling up to 200%), Android display size, dark mode, bold text, increased contrast, reduced motion, colour inversion and filters, right-to-left languages, landscape and split-screen or foldable layouts, and the screen readers that rely on all of these. These settings are how many people make their phones usable, and screens that look fine at default often break: text is cut off, buttons overlap, or content disappears.

This list is for mobile developers, designers and QA testers. Android facts were checked against Android Developers documentation on 28 October 2026; Apple's Human Interface Guidelines cover Dynamic Type. For the wider QA plan, see mobile app testing.

1. iOS Dynamic Type at the largest sizes. Use the system text styles so text scales with the user's setting, and test at the largest standard size and the accessibility sizes. Let text wrap rather than truncate, and switch side-by-side layouts to stacked ones at large sizes.

2. Android font scaling up to 200%. Android 14 supports font scaling up to 200% with a non-linear curve. Android's guidance: specify text sizes and line heights in sp units, do not use sp for padding, avoid hard-coded scaling maths, and test at 200%.

3. Fixed-height containers. Buttons, tabs, cards and list rows with fixed heights clip enlarged text. Let them grow with content.

4. Text in images and custom-drawn text. Text drawn into images, charts or canvases does not scale. Use real text, or provide scaled alternatives.

5. Android display size. Separate from font size, display size makes everything larger and reduces the effective screen width. Check that layouts still fit and nothing important moves off-screen.

6. Dark mode. Check every screen, including images with transparent backgrounds, charts, maps, web views and third-party SDK screens. Hard-coded colours are the usual problem; use semantic colours.

7. Bold text and increased contrast. iOS and Android offer bold text and higher-contrast options. Bold text makes strings wider; increased contrast should strengthen borders and text colours where you use custom styles.

8. Colour inversion and filters. Users with low vision or colour-vision deficiency may invert colours or apply filters. Make sure meaning does not rely on colour alone, and that photos are not inverted where the platform lets you opt them out.

9. Reduced motion. iOS Reduce Motion and Android's option to remove animations signal that users want less movement. Replace large movements, parallax and auto-playing animation with simple fades or none. WCAG's guidance on animation from interactions follows the same principle.

10. Landscape, split-screen and foldables. Rotating, using multi-window on Android tablets or unfolding a foldable changes the available space mid-session. Check layouts and that state is kept when the configuration changes.

11. Right-to-left languages. With an Arabic or Hebrew device language, layouts mirror. Test even before you translate, to catch hard-coded left and right alignment. See localisation layout problems.

12. Screen readers with these settings on. VoiceOver and TalkBack users often also use large text or high contrast. Test key journeys with a screen reader and large text together, checking labels, reading order and that enlarged elements remain reachable. See accessibility testing tools.

Display settings are not edge cases; they are how many people use their phones. Build with system text styles and sp units, avoid fixed heights and hard-coded colours, and add the largest text size, dark mode, reduced motion and a right-to-left language to every release test. For designing accessibly from the start, see accessible UI/UX design.

Android Developers, Android 14 features: non-linear font scaling to 200%. Apple Human Interface Guidelines, typography and Dynamic Type. W3C WCAG 2.2: 1.4.4 Resize Text, 1.4.10 Reflow, 2.3.3 Animation from Interactions. Accessed 28 October 2026.