Struct glyph_brush_draw_cache::DrawCacheBuilder [−][src]
pub struct DrawCacheBuilder { /* fields omitted */ }
Expand description
Builder & rebuilder for DrawCache
.
Example
use glyph_brush_draw_cache::DrawCache;
// Create a cache with all default values set explicitly
// equivalent to `DrawCache::builder().build()`
let default_cache = DrawCache::builder()
.dimensions(256, 256)
.scale_tolerance(0.1)
.position_tolerance(0.1)
.pad_glyphs(true)
.align_4x4(false)
.multithread(true)
.build();
// Create a cache with all default values, except with a dimension of 1024x1024
let bigger_cache = DrawCache::builder().dimensions(1024, 1024).build();
Implementations
width
& height
dimensions of the 2D texture that will hold the
cache contents on the GPU.
This must match the dimensions of the actual texture used, otherwise
cache_queued
will try to cache into coordinates outside the bounds of
the texture.
Example (set to default value)
let cache = DrawCache::builder().dimensions(256, 256).build();
Specifies the tolerances (maximum allowed difference) for judging
whether an existing glyph in the cache is close enough to the
requested glyph in scale to be used in its place. Due to floating
point inaccuracies a min value of 0.001
is enforced.
Both scale_tolerance
and position_tolerance
are measured in pixels.
Tolerances produce even steps for scale and subpixel position. Only a
single glyph texture will be used within a single step. For example,
scale_tolerance = 0.1
will have a step 9.95-10.05
so similar glyphs
with scale 9.98
& 10.04
will match.
A typical application will produce results with no perceptible
inaccuracies with scale_tolerance
and position_tolerance
set to
0.1. Depending on the target DPI higher tolerance may be acceptable.
Example (set to default value)
let cache = DrawCache::builder().scale_tolerance(0.1).build();
Specifies the tolerances (maximum allowed difference) for judging
whether an existing glyph in the cache is close enough to the requested
glyph in subpixel offset to be used in its place. Due to floating
point inaccuracies a min value of 0.001
is enforced.
Both scale_tolerance
and position_tolerance
are measured in pixels.
Tolerances produce even steps for scale and subpixel position. Only a
single glyph texture will be used within a single step. For example,
scale_tolerance = 0.1
will have a step 9.95-10.05
so similar glyphs
with scale 9.98
& 10.04
will match.
Note that since position_tolerance
is a tolerance of subpixel
offsets, setting it to 1.0 or higher is effectively a “don’t care”
option.
A typical application will produce results with no perceptible
inaccuracies with scale_tolerance
and position_tolerance
set to
0.1. Depending on the target DPI higher tolerance may be acceptable.
Example (set to default value)
let cache = DrawCache::builder().position_tolerance(0.1).build();
Pack glyphs in texture with a padding of a single zero alpha pixel to avoid bleeding from interpolated shader texture lookups near edges.
If glyphs are never transformed this may be set to false
to slightly
improve the glyph packing.
Example (set to default value)
let cache = DrawCache::builder().pad_glyphs(true).build();
Align glyphs in texture to 4x4 texel boundaries.
If your backend requires texture updates to be aligned to 4x4 texel
boundaries (e.g. WebGL), this should be set to true
.
Example (set to default value)
let cache = DrawCache::builder().align_4x4(false).build();
When multiple CPU cores are available spread rasterization work across all cores.
Significantly reduces worst case latency in multicore environments.
Platform-specific behaviour
This option has no effect on wasm32.
Example (set to default value)
let cache = DrawCache::builder().multithread(true).build();
Rebuilds a DrawCache
with new attributes. All cached glyphs are cleared,
however the glyph queue is retained unmodified.
Panics
scale_tolerance
or position_tolerance
are less than or equal to
zero.
Example
// Rebuild the cache with different dimensions
cache.to_builder().dimensions(768, 768).rebuild(&mut cache);
Trait Implementations
Auto Trait Implementations
impl RefUnwindSafe for DrawCacheBuilder
impl Send for DrawCacheBuilder
impl Sync for DrawCacheBuilder
impl Unpin for DrawCacheBuilder
impl UnwindSafe for DrawCacheBuilder
Blanket Implementations
Mutably borrows from an owned value. Read more