| // FCS Glass - src/core/layout.h | |
| // | |
| // Implements: A2 (dp -> whole physical pixels, round half up, at every | |
| // supported scale factor; hairlines exactly 1 physical px), | |
| // A3 (radii: window / card / control, pill = height/2 for chips | |
| // and toggles only, inner radius never above outer minus inset). | |
| // | |
| // PURE LOGIC. No windows, no D3D, no project headers. That is a hard | |
| // requirement rather than a style preference: tools/extract_logic.py lifts these | |
| // bodies VERBATIM into tools/generated_logic.inc so tools/logic_harness.cpp can | |
| // exercise them on any machine, Windows or not. One #include <windows.h> on | |
| // this path would take the entire portable test suite with it. | |
| // | |
| // This file owns ONE rounding rule for dp -> px. platform/dpi.h's DpToPx does | |
| // the same conversion, and it could not simply call this one: extract_logic.py | |
| // lifts function bodies as bare text, so a body referring to core::SnapPx would | |
| // arrive in the harness with nothing to resolve against. Rather than duplicate | |
| // the rule silently, the duplication is pinned by a test - the suite asserts | |
| // DpToPx and SnapPx return identical values for every spec'd scale factor AND | |
| // for negative dp, which is the input that broke DpToPx (BUG-30). A future edit | |
| // that moves one and not the other fails the suite instead of shipping a 1 px | |
| // disagreement that shows up as a seam. | |
| namespace fcs { | |
| namespace core { | |
| // A2. The dp -> physical pixel conversion: round half up, ties toward | |
| // +infinity, floored explicitly. `static_cast<int>(x + 0.5f)` agrees with this | |
| // only while x is non-negative, because the cast truncates toward zero. | |
| int SnapPx(float dp, float scale); | |
| // A2. A 1 dp hairline is EXACTLY 1 physical pixel at every scale factor. This is | |
| // the one measurement that must NOT scale, or borders thicken as the user drags | |
| // the scale slider and a 2 px border reads as a different design. | |
| constexpr int kHairlinePx = 1; | |
| // A3. Corner radii in dp. `window_dp` is 0 on the Classic profile, which is a | |
| // design decision rather than an oversight, so it is a field and not a constant. | |
| struct RadiusSet { | |
| int window_dp = 8; | |
| int card_dp = 8; | |
| int control_dp = 4; | |
| }; | |
| // A3. An inner radius can never exceed the outer radius minus the inset between | |
| // them; past that the inner corner crosses the outer one and the outline | |
| // self-intersects. Clamped rather than rejected: a clamp degrades to a valid | |
| // shape, a rejection loses the widget. | |
| int InnerRadiusClamp(int outer_px, int inset_px); | |
| // A3. A pill is height/2 - but ONLY for chips and toggles. `allow_pill` is an | |
| // explicit argument so a card cannot acquire a stadium outline by accident. | |
| int PillRadiusPx(int height_px, bool allow_pill); | |
| } // namespace core | |
| } // namespace fcs | |