зеркало из https://github.com/mozilla/gecko-dev.git
52 строки
2.4 KiB
Rust
52 строки
2.4 KiB
Rust
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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extern crate app_units;
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extern crate euclid;
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#[macro_use] extern crate heapsize;
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use app_units::{Au, MAX_AU, MIN_AU};
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use euclid::{Point2D, Rect, Size2D};
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// Units for use with euclid::length and euclid::scale_factor.
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/// A normalized "pixel" at the default resolution for the display.
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///
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/// Like the CSS "px" unit, the exact physical size of this unit may vary between devices, but it
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/// should approximate a device-independent reference length. This unit corresponds to Android's
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/// "density-independent pixel" (dip), Mac OS X's "point", and Windows "device-independent pixel."
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///
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/// The relationship between DevicePixel and DeviceIndependentPixel is defined by the OS. On most low-dpi
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/// screens, one DeviceIndependentPixel is equal to one DevicePixel. But on high-density screens it can be
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/// some larger number. For example, by default on Apple "retina" displays, one DeviceIndependentPixel equals
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/// two DevicePixels. On Android "MDPI" displays, one DeviceIndependentPixel equals 1.5 device pixels.
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///
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/// The ratio between DeviceIndependentPixel and DevicePixel for a given display be found by calling
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/// `servo::windowing::WindowMethods::hidpi_factor`.
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#[derive(Clone, Copy, Debug)]
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pub enum DeviceIndependentPixel {}
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known_heap_size!(0, DeviceIndependentPixel);
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// An Au is an "App Unit" and represents 1/60th of a CSS pixel. It was
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// originally proposed in 2002 as a standard unit of measure in Gecko.
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// See https://bugzilla.mozilla.org/show_bug.cgi?id=177805 for more info.
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#[inline(always)]
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pub fn max_rect() -> Rect<Au> {
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Rect::new(Point2D::new(MIN_AU / 2, MIN_AU / 2), Size2D::new(MAX_AU, MAX_AU))
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}
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/// A helper function to convert a rect of `f32` pixels to a rect of app units.
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pub fn f32_rect_to_au_rect(rect: Rect<f32>) -> Rect<Au> {
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Rect::new(Point2D::new(Au::from_f32_px(rect.origin.x), Au::from_f32_px(rect.origin.y)),
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Size2D::new(Au::from_f32_px(rect.size.width), Au::from_f32_px(rect.size.height)))
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}
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/// A helper function to convert a rect of `Au` pixels to a rect of f32 units.
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pub fn au_rect_to_f32_rect(rect: Rect<Au>) -> Rect<f32> {
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Rect::new(Point2D::new(rect.origin.x.to_f32_px(), rect.origin.y.to_f32_px()),
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Size2D::new(rect.size.width.to_f32_px(), rect.size.height.to_f32_px()))
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}
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