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Merged
triniwiz merged 9 commits into from
Sep 30, 2026
Merged

Android: threaded WebGL, 2D render-thread backpressure, % sizes under MasonKit #174

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e34104c
fix(core): destroy the Vulkan swapchain and its image views on drop
triniwiz Sep 30, 2026
869221f
fix(canvas): hand a % size to MasonKit on Android and iOS too
triniwiz Sep 30, 2026
3ecb6ca
perf(android): create WebGL EGL contexts at low GPU priority
triniwiz Sep 30, 2026
4291a06
feat(webgl): run Android WebGL contexts on a dedicated thread
triniwiz Sep 30, 2026
a35a84f
fix(2d): stop a lagging render thread merging frames without limit
triniwiz Sep 30, 2026
226748a
perf(2d): draw Android canvases into a multisampled offscreen, 8 bits…
triniwiz Sep 30, 2026
10ae9c2
perf(webgl): skip a detaching context's queued presents
triniwiz Sep 30, 2026
31a0040
fix(2d): opaque surfaces are RGB888x over an RGB8 buffer
triniwiz Sep 30, 2026
8164db1
perf: read the canvases-behind count from shared memory
triniwiz Sep 30, 2026
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58 changes: 26 additions & 32 deletions crates/canvas-2d/src/context/surface_gl.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,17 @@ fn gl_interface() -> Option<Interface> {
}
}

/// 8 bits a channel even when opaque, as on the web: at 5-6 bits (RGB565) a translucent fill never
/// converges on its colour, so a trail fading out leaves a permanent tint. Opaque is RGB888x, whose
/// alpha reads back as 255 whatever was drawn.
fn color_type_for(alpha: bool) -> ColorType {
if alpha {
ColorType::RGBA8888
} else {
ColorType::RGB888x
}
}

fn with_offscreen(
ctx: &mut gpu::DirectContext,
window: skia_safe::Surface,
Expand All @@ -28,23 +39,24 @@ fn with_offscreen(
) -> (skia_safe::Surface, Option<skia_safe::Surface>) {
#[cfg(target_os = "android")]
{
let (color_type, alpha_type) = if alpha {
(ColorType::RGBA8888, AlphaType::Premul)
} else {
(ColorType::RGB565, AlphaType::Opaque)
};
let color_type = color_type_for(alpha);
let alpha_type = if alpha { AlphaType::Premul } else { AlphaType::Opaque };
let info = ImageInfo::new(
ISize::new(window.width(), window.height()),
color_type,
alpha_type,
color_space,
);
let props = window.props().clone();
// Multisampled, so Skia draws antialiased paths on the GPU instead of rasterizing their
// coverage on this thread and uploading it every frame; on a tiled GPU the samples mostly
// stay in tile memory.
let samples = ctx.max_surface_sample_count_for_color_type(color_type).min(4);
if let Some(offscreen) = gpu::surfaces::render_target(
ctx,
gpu::Budgeted::Yes,
&info,
Some(0),
Some(samples),
gpu::SurfaceOrigin::TopLeft,
Some(&props),
false,
Expand All @@ -69,8 +81,9 @@ fn draws_to_window(gl: &canvas_core::gpu::gl::GLContext) -> bool {
}
}

const GR_GL_RGB565: u32 = 0x8D62;
const GR_GL_RGBA8: u32 = 0x8058;
/// An opaque config's buffer, which RGB888x wraps.
const GR_GL_RGB8: u32 = 0x8051;

#[cfg(feature = "gl")]
impl Context {
Expand Down Expand Up @@ -150,11 +163,7 @@ impl Context {

let mut frame_buffer = gpu::gl::FramebufferInfo::from_fboid(buffer_id[0] as u32);

if alpha {
frame_buffer.format = GR_GL_RGBA8;
} else {
frame_buffer.format = GR_GL_RGB565;
}
frame_buffer.format = if alpha { GR_GL_RGBA8 } else { GR_GL_RGB8 };

let target = gpu::backend_render_targets::make_gl(
(width as i32, height as i32),
Expand All @@ -166,10 +175,7 @@ impl Context {
skia_safe::SurfacePropsFlags::default(),
PixelGeometry::Unknown,
);
let mut color_type = ColorType::RGBA8888;
if !alpha {
color_type = ColorType::RGB565;
}
let color_type = color_type_for(alpha);

let surface = gpu::surfaces::wrap_backend_render_target(
&mut ctx,
Expand Down Expand Up @@ -310,16 +316,12 @@ impl Context {
let mut window_surface = None;
let mut engine = SurfaceEngine::GL;
let surface = if bounds.is_empty() {
let color_type = if alpha {
ColorType::RGBA8888
} else {
ColorType::RGB565
};
let color_type = color_type_for(alpha);

let alpha_type = if alpha {
AlphaType::Unpremul
} else {
AlphaType::Premul
AlphaType::Opaque
};

let mut width = width;
Expand Down Expand Up @@ -353,11 +355,7 @@ impl Context {

let mut frame_buffer = gpu::gl::FramebufferInfo::from_fboid(buffer_id as u32);

if alpha {
frame_buffer.format = GR_GL_RGBA8;
} else {
frame_buffer.format = GR_GL_RGB565;
}
frame_buffer.format = if alpha { GR_GL_RGBA8 } else { GR_GL_RGB8 };

let target = gpu::backend_render_targets::make_gl(
(width as i32, height as i32),
Expand All @@ -370,11 +368,7 @@ impl Context {
skia_safe::SurfacePropsFlags::default(),
PixelGeometry::Unknown,
);
let mut color_type = ColorType::RGBA8888;

if !alpha {
color_type = ColorType::RGB565;
}
let color_type = color_type_for(alpha);

let surface = gpu::surfaces::wrap_backend_render_target(
&mut ctx,
Expand Down
96 changes: 60 additions & 36 deletions crates/canvas-android/src/jni_compat/org_nativescript_canvas_NSCCanvas.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -250,6 +250,7 @@ pub extern "system" fn nativeInitWebGL(
desynchronized: jboolean,
xr_compatible: jboolean,
version: jint,
threaded: jboolean,
) -> jlong {
unsafe {
let interface = env.get_native_interface();
Expand All @@ -261,7 +262,12 @@ pub extern "system" fn nativeInitWebGL(
return 0;
}
if let Ok(power_preference) = PowerPreference::try_from(power_preference) {
let context = canvas_c::canvas_native_webgl_create(
let create = if threaded == JNI_TRUE {
canvas_c::canvas_native_webgl_create_threaded
} else {
canvas_c::canvas_native_webgl_create
};
let context = create(
window.ptr().as_ptr() as _,
window.width(),
window.height(),
Expand Down Expand Up @@ -308,6 +314,7 @@ pub extern "system" fn nativeInitWebGLNoSurface(
desynchronized: jboolean,
xr_compatible: jboolean,
version: jint,
threaded: jboolean,
) -> jlong {
if version == 2 && !GLContext::has_gl2support() {
return 0;
Expand All @@ -317,7 +324,12 @@ pub extern "system" fn nativeInitWebGLNoSurface(
let height = height.max(1);

if let Ok(power_preference) = PowerPreference::try_from(power_preference) {
let context = canvas_c::canvas_native_webgl_create_no_window(
let create = if threaded == JNI_TRUE {
canvas_c::canvas_native_webgl_create_no_window_threaded
} else {
canvas_c::canvas_native_webgl_create_no_window
};
let context = create(
width,
height,
version as i32,
Expand Down Expand Up @@ -458,19 +470,23 @@ pub extern "system" fn nativeUpdateWebGLSurface(
return;
}
let context = context as *mut WebGLState;
let context = unsafe { &mut *context };
let context = unsafe { &*context };
unsafe {
if let Some(window) = NativeWindow::from_surface(env.get_native_interface(), surface) {
// NativeWindow::ptr() is NonNull<ANativeWindow>; the as *mut c_void cast
// preserves non-nullness, but guard defensively to avoid a panic.
let Some(nn_ptr) = NonNull::new(window.ptr().as_ptr() as _) else { return };
context.get_inner_mut().set_window_surface(
window.width(),
window.height(),
nn_ptr,
);
context.get_inner().make_current();
drop(env);
let (width, height) = (window.width(), window.height());
// Queued, not waited on: this runs from the view's surface callbacks, and blocking them
// on a thread that may be waiting for a buffer from this window can deadlock its queue.
// `window` holds a reference until the job is done with it.
context.post(move |state| {
// NativeWindow::ptr() is NonNull<ANativeWindow>; the as *mut c_void cast
// preserves non-nullness, but guard defensively to avoid a panic.
let Some(nn_ptr) = NonNull::new(window.ptr().as_ptr() as _) else {
return;
};
state.set_window_surface(width, height, nn_ptr);
state.make_current();
});
}
}
}
Expand Down Expand Up @@ -616,9 +632,12 @@ fn native_update_gl_no_surface(width: jint, height: jint, context: jlong) {
return;
}
let context = context as *mut WebGLState;
let context = unsafe { &mut *context };
context.get_inner().make_current();
context.get_inner_mut().resize_pbuffer(width, height);
let context = unsafe { &*context };
// Waited on: when the window is going away this is how the context lets go of it.
context.detach(|state| {
state.make_current();
state.resize_pbuffer(width, height);
});
}

#[no_mangle]
Expand Down Expand Up @@ -676,7 +695,8 @@ pub extern "system" fn nativeMakeWebGLCurrent(gl_context: jlong) -> jboolean {
}
let gl_context = gl_context as *mut WebGLState;
let gl_context = unsafe { &*gl_context };
if gl_context.get_inner().make_current() {
// A threaded context is made current on its own thread, where everything that uses it runs.
if gl_context.sync(|state| state.make_current()) {
return JNI_TRUE;
}
JNI_FALSE
Expand All @@ -693,7 +713,8 @@ pub extern "system" fn nativeMakeWebGLCurrentNormal(
}
let gl_context = gl_context as *mut WebGLState;
let gl_context = unsafe { &*gl_context };
if gl_context.get_inner().make_current() {
// A threaded context is made current on its own thread, where everything that uses it runs.
if gl_context.sync(|state| state.make_current()) {
return JNI_TRUE;
}
JNI_FALSE
Expand Down Expand Up @@ -851,32 +872,35 @@ pub extern "system" fn nativeWriteCurrentWebGLContextToBitmap(
}

let context = context as *mut WebGLState;
let context = unsafe { &mut *context };
let context = unsafe { &*context };

unsafe {
crate::utils::image::bitmap_handler(
&env,
bitmap,
Box::new(move |cb| {
if let Some((image_data, info)) = cb {
context.get_inner().make_current();
// Use checked arithmetic — width/height are u32 and can overflow on multiply.
let buf_size = (info.width() as usize)
.checked_mul(info.height() as usize)
.and_then(|n| n.checked_mul(4));
let Some(buf_size) = buf_size else { return };
let mut buf = vec![0u8; buf_size];
gl_bindings::Flush();
gl_bindings::ReadPixels(
0,
0,
info.width() as i32,
info.height() as i32,
gl_bindings::RGBA as std::os::raw::c_uint,
gl_bindings::UNSIGNED_BYTE as std::os::raw::c_uint,
buf.as_mut_ptr() as *mut c_void,
);
image_data.copy_from_slice(buf.as_slice());
// The bitmap stays locked while this waits for the read.
context.sync(|state| {
state.make_current();
// Use checked arithmetic — width/height are u32 and can overflow on multiply.
let buf_size = (info.width() as usize)
.checked_mul(info.height() as usize)
.and_then(|n| n.checked_mul(4));
let Some(buf_size) = buf_size else { return };
let mut buf = vec![0u8; buf_size];
gl_bindings::Flush();
gl_bindings::ReadPixels(
0,
0,
info.width() as i32,
info.height() as i32,
gl_bindings::RGBA as std::os::raw::c_uint,
gl_bindings::UNSIGNED_BYTE as std::os::raw::c_uint,
buf.as_mut_ptr() as *mut c_void,
);
image_data.copy_from_slice(buf.as_slice());
});
}
}),
)
Expand Down
28 changes: 16 additions & 12 deletions crates/canvas-android/src/jni_compat/org_nativescript_canvas_NSCWebGLRenderingContext.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -23,21 +23,23 @@ pub extern "system" fn nativeTexImage2D(
}

let context = context as *mut WebGLState;
let context = unsafe { &mut *context };
let context = unsafe { &*context };

let bytes = crate::utils::image::get_bytes_from_bitmap(&env, bitmap);

if let Some((bytes, info)) = bytes {
context.get_inner().make_current();
let width = info.width();
let height = info.height();
unsafe {
let stride = info.stride();
// The bitmap's bytes are a copy, so the upload can queue.
context.post(move |state| unsafe {
state.make_current();
if flip_y == JNI_TRUE {
let mut buffer = bytes;
canvas_webgl::utils::gl::flip_in_place(
buffer.as_mut_ptr(),
buffer.len(),
info.stride() as usize,
stride as usize,
height as usize,
);

Expand Down Expand Up @@ -65,7 +67,7 @@ pub extern "system" fn nativeTexImage2D(
bytes.as_ptr() as *const c_void,
);
}
}
});
}
}

Expand All @@ -88,21 +90,23 @@ pub extern "system" fn nativeTexSubImage2D(
}

let context = context as *mut WebGLState;
let context = unsafe { &mut *context };
let context = unsafe { &*context };

let bytes = crate::utils::image::get_bytes_from_bitmap(&env, bitmap);

if let Some((bytes, info)) = bytes {
unsafe {
context.get_inner().make_current();
let width = info.width();
let height = info.height();
let width = info.width();
let height = info.height();
let stride = info.stride();
// The bitmap's bytes are a copy, so the upload can queue.
context.post(move |state| unsafe {
state.make_current();
if flip_y == JNI_TRUE {
let mut buffer = bytes;
canvas_webgl::utils::gl::flip_in_place(
buffer.as_mut_ptr(),
buffer.len(),
info.stride() as usize,
stride as usize,
height as usize,
);

Expand Down Expand Up @@ -130,6 +134,6 @@ pub extern "system" fn nativeTexSubImage2D(
bytes.as_ptr() as *const c_void,
);
}
}
});
}
}
8 changes: 4 additions & 4 deletions crates/canvas-android/src/lib.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -111,8 +111,8 @@ pub extern "system" fn JNI_OnLoad(vm: JavaVM, _reserved: *const c_void) -> jint

let canvas_signatures = if ret >= ANDROID_O {
let mut ret = vec![
"(Landroid/view/Surface;ZZZZIZZZZZI)J",
"(IIZZZZIZZZZZI)J",
"(Landroid/view/Surface;ZZZZIZZZZZIZ)J",
"(IIZZZZIZZZZZIZ)J",
"(IILandroid/view/Surface;ZFIFII)J",
"(Landroid/view/Surface;J)V",
"(Landroid/view/Surface;IIJ)V",
Expand Down Expand Up @@ -149,8 +149,8 @@ pub extern "system" fn JNI_OnLoad(vm: JavaVM, _reserved: *const c_void) -> jint
ret
} else {
let mut ret = vec![
"!(Landroid/view/Surface;ZZZZIZZZZZI)J",
"!(IIZZZZIZZZZZI)J",
"(Landroid/view/Surface;ZZZZIZZZZZIZ)J",
"(IIZZZZIZZZZZIZ)J",
"!(IILandroid/view/Surface;ZFIFII)J",
"!(Landroid/view/Surface;J)V",
"!(Landroid/view/Surface;IIJ)V",
Expand Down
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