Plan DPI and text-layout tests — Build the smallest useful slice

PART I

Warm-up

Reconnect with a useful idea before starting plan dpi and text-layout tests. In one or two sentences, describe the input, output or host boundary from the previous exercise that this lesson builds on. If you are arriving directly, skim the worked example first; there is no locked prerequisite.

A rough note is enough. You can revise it after the example.

PART II

Instruction & guided example

Build a minimal DPI test matrix

DPI and text layout need explicit unit and measurement contracts. A logical layout size differs from physical pixels, and glyph measurements differ across fonts, scales and languages. Use small numeric budgets for predictions and native observations for actual rendering; no WUIX engine runs on this school site.

A button has logical size100x30. Supported fixture scales are1,1.5,2. Required hit area remains the same logical rectangle at each scale. No fractional-pixel rounding arises.

Worked reasoning: Expected physical rectangles are100x30,150x45 and200x60. A test should compare label visibility and action hit area at each scale, not only screenshot pixel count.

Failed alternative: Testing only scale1 cannot establish that scaling is applied once or that the native hit target tracks the visual rectangle.

Worked reasoning and supplied artifact

Scale |Logical |Physical
1 |100x30 |100x30
1.5 |100x30 |150x45
2 |100x30 |200x60
Native checks:label clarity,visual bounds,matching hit area

Illustrative example from the proposed WillowScript design. The language and WUIX/WMATH/WDB/WAUDIO/WTMP services are not implemented in the supplied source. This site has no interpreter, VM or native host and does not execute or certify the snippet.

Try the guided change

Reconstruct the supplied worked case first: list its inputs, intermediate decisions and final artifact. Compare each row with the explanation and identify exactly where the rejected alternative fails. Then use the changed inputs in Part IV for independent work.

• Write the supplied inputs and initial state before following the example.
• Reconstruct each intermediate calculation or host decision, then compare with the worked artifact.
• Explain why the contrasting alternative fails before attempting the changed inputs in Part IV.

PART III

Take a breather

Step back after the guided example. Look away from the screen, stretch, or reread your prediction. This is an optional learning pause, not a timer or an assessment gate.

When you return, try to name the lesson’s key idea without copying its wording. If that feels difficult, return to Part II and trace one line rather than restarting the entire lesson.

PART IV

Independent practice

Project context: Accessible service console. Build a small, understandable change around plan dpi and text-layout tests.

Prepare scales1,2,3 for a logical80x24 control. Include a native interaction observation for each.

What to produce

A DPI prediction matrix and target-specific native observation checklist.

• State the intended behavior in a sentence before editing.
• Use only source-backed syntax and the host services whose contract you have been given.
• Record a normal case and a boundary or unavailable-resource case.
• Label hand predictions separately from anything actually measured in a supplied toolchain.

Syntax colors are a reading aid, not a compiler. The line you are editing stays uncolored until you move to a different line; capitalization is never changed. Drafts stay on this browser and code is not executed.

import wuix.widget.button;
import wuix.layout;
domain Login {
    const screen = {
        layout: { type: "column", padding: [24, 32], gap: 16 },
        components: [{ type: "text", value: "Welcome back" }]
    };
    fnc show() -> void {
        wuix.mount("main", screen);
    }
}

PART V

Self-check

Use this check to notice what to revisit. It does not award a private course grade, block another page or claim to verify compiled code. Every answer has a learning explanation.

You may keep exploring even if you are unsure. Use the hint, compare the trace, and revise your explanation.

PART VI

Recap & small task

Bring the idea back to the mod feature you are building. A useful recap connects the mechanism to a decision you can make in your own code.

• Build a minimal DPI test matrix
• Prepare scales1,2,3 for a logical80x24 control. Include a native interaction observation for each.
• Separate source-backed behavior, host requirements and untested predictions.

One small recap task

Measure visual and interactive bounds together.

This marks your personal practice record only. It is not a certification or an official workspace assessment.