bitmap: Add compress()/compress_raw() fns since API 30 (#440)

Map the new compression functions that are available in API level 30,
which also take a `DataSpace` that has recently been added in #438.

Also turn `BitmapError` into a proper `non_exhaustive` `enum` with
`num_enum`'s `catch_all` parser, similar to `MediaError`.

Author: MarijnS95

ndk/CHANGELOG.md

@@ -32,6 +32,9 @@
 - **Breaking:** looper: Provide `event` value to file descriptor poll callback. (#435)
 - **Breaking:** `HardwareBufferFormat` is no longer exported from `hardware_buffer` and `native_window`, and can only be reached through the `hardware_buffer_format` module. (#436)
 - **Breaking:** `get_` prefixes have been removed from all public functions in light of the [C-GETTER](https://rust-lang.github.io/api-guidelines/naming.html#getter-names-follow-rust-convention-c-getter) convention. (#437)
+- Add `DataSpace` type and relevant functions on `Bitmap` and `NativeWindow`. (#438)
+- bitmap: Add `Bitmap::compress()` and `Bitmap::compress_raw()` functions. (#440)
+- **Breaking:** Turn `BitmapError` into a `non_exhaustive` `enum`. (#440)
 
 # 0.7.0 (2022-07-24)
 

ndk/src/bitmap.rs

@@ -7,37 +7,47 @@
 #![cfg(feature = "bitmap")]
 
 use jni_sys::{jobject, JNIEnv};
-use num_enum::{IntoPrimitive, TryFromPrimitive, TryFromPrimitiveError};
-use std::mem::MaybeUninit;
+use num_enum::{FromPrimitive, IntoPrimitive, TryFromPrimitive, TryFromPrimitiveError};
+use std::{error, fmt, mem::MaybeUninit};
+use thiserror::Error;
 
 #[cfg(feature = "api-level-30")]
 use crate::data_space::DataSpace;
 #[cfg(feature = "api-level-30")]
 use crate::hardware_buffer::HardwareBufferRef;
 
 #[repr(i32)]
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, FromPrimitive, IntoPrimitive)]
+#[non_exhaustive]
 pub enum BitmapError {
-    Unknown,
     #[doc(alias = "ANDROID_BITMAP_RESULT_ALLOCATION_FAILED")]
     AllocationFailed = ffi::ANDROID_BITMAP_RESULT_ALLOCATION_FAILED,
     #[doc(alias = "ANDROID_BITMAP_RESULT_BAD_PARAMETER")]
     BadParameter = ffi::ANDROID_BITMAP_RESULT_BAD_PARAMETER,
     #[doc(alias = "ANDROID_BITMAP_RESULT_JNI_EXCEPTION")]
     JniException = ffi::ANDROID_BITMAP_RESULT_JNI_EXCEPTION,
+    // Use the OK discriminant, as no-one will be able to call `as i32` and only has access to the
+    // constants via `From` provided by `IntoPrimitive` which reads the contained value.
+    #[num_enum(catch_all)]
+    Unknown(i32) = ffi::AAUDIO_OK,
 }
 
+impl fmt::Display for BitmapError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{:?}", self)
+    }
+}
+
+impl error::Error for BitmapError {}
+
 pub type Result<T, E = BitmapError> = std::result::Result<T, E>;
 
 impl BitmapError {
     pub(crate) fn from_status(status: i32) -> Result<()> {
-        Err(match status {
-            ffi::ANDROID_BITMAP_RESULT_SUCCESS => return Ok(()),
-            ffi::ANDROID_BITMAP_RESULT_ALLOCATION_FAILED => BitmapError::AllocationFailed,
-            ffi::ANDROID_BITMAP_RESULT_BAD_PARAMETER => BitmapError::BadParameter,
-            ffi::ANDROID_BITMAP_RESULT_JNI_EXCEPTION => BitmapError::JniException,
-            _ => BitmapError::Unknown,
-        })
+        match status {
+            ffi::ANDROID_BITMAP_RESULT_SUCCESS => Ok(()),
+            x => Err(Self::from(x)),
+        }
     }
 }
 
@@ -153,6 +163,132 @@ impl Bitmap {
             Ok(HardwareBufferRef::from_ptr(non_null))
         }
     }
+
+    /// [Lock] the pixels in `self` and compress them as described by [`info()`].
+    ///
+    /// Unlike [`compress_raw()`] this requires a [`Bitmap`] object (as `self`) backed by a
+    /// [`jobject`].
+    ///
+    /// # Parameters
+    /// - `format`: [`BitmapCompressFormat`] to compress to.
+    /// - `quality`: Hint to the compressor, `0-100`.  The value is interpreted differently
+    ///   depending on [`BitmapCompressFormat`].
+    /// - `compress_callback`: Closure that writes the compressed data.  Will be called on the
+    ///   current thread, each time the compressor has compressed more data that is ready to be
+    ///   written.  May be called more than once for each call to this method.
+    ///
+    /// [Lock]: Self::lock_pixels()
+    /// [`info()`]: Self::info()
+    /// [`compress_raw()`]: Self::compress_raw()
+    #[cfg(feature = "api-level-30")]
+    #[doc(alias = "AndroidBitmap_compress")]
+    pub fn compress<F: FnMut(&[u8]) -> Result<(), ()>>(
+        &self,
+        format: BitmapCompressFormat,
+        quality: i32,
+        compress_callback: F,
+    ) -> Result<(), BitmapCompressError> {
+        let info = self.info()?;
+        let data_space = self.data_space()?;
+        let pixels = self.lock_pixels()?;
+        // SAFETY: When lock_pixels() succeeds, assume it returns a valid pointer that stays
+        // valid until we call unlock_pixels().
+        let result = unsafe {
+            Self::compress_raw(
+                &info,
+                data_space,
+                pixels,
+                format,
+                quality,
+                compress_callback,
+            )
+        };
+        self.unlock_pixels()?;
+        result
+    }
+
+    /// Compress `pixels` as described by `info`.
+    ///
+    /// Unlike [`compress()`] this takes a raw pointer to pixels and does not need a [`Bitmap`]
+    /// object backed by a [`jobject`].
+    ///
+    /// # Parameters
+    /// - `info`: Description of the pixels to compress.
+    /// - `data_space`: [`DataSpace`] describing the color space of the pixels.  Should _not_ be
+    ///   [`DataSpace::Unknown`] [^1].
+    /// - `pixels`: Pointer to pixels to compress.
+    /// - `format`: [`BitmapCompressFormat`] to compress to.
+    /// - `quality`: Hint to the compressor, `0-100`.  The value is interpreted differently
+    ///   depending on [`BitmapCompressFormat`].
+    /// - `compress_callback`: Closure that writes the compressed data.  Will be called on the
+    ///   current thread, each time the compressor has compressed more data that is ready to be
+    ///   written.  May be called more than once for each call to this method.
+    ///
+    /// [`compress()`]: Self::compress()
+    /// [^1]: <https://cs.android.com/android/platform/superproject/main/+/main:frameworks/base/libs/hwui/apex/android_bitmap.cpp;l=275-279;drc=7ba5c2fb3d1e35eb37a9cc522b30ba51f49ea491>
+    #[cfg(feature = "api-level-30")]
+    #[doc(alias = "AndroidBitmap_compress")]
+    pub unsafe fn compress_raw<F: FnMut(&[u8]) -> Result<(), ()>>(
+        info: &BitmapInfo,
+        data_space: DataSpace,
+        pixels: *const std::ffi::c_void,
+        format: BitmapCompressFormat,
+        quality: i32,
+        compress_callback: F,
+    ) -> Result<(), BitmapCompressError> {
+        if data_space == DataSpace::Unknown {
+            return Err(BitmapCompressError::DataSpaceUnknown);
+        }
+
+        use std::{any::Any, ffi::c_void, panic::AssertUnwindSafe};
+        struct CallbackState<F: FnMut(&[u8]) -> Result<(), ()>> {
+            callback: F,
+            panic: Option<Box<dyn Any + Send>>,
+        }
+        let mut cb_state = CallbackState::<F> {
+            callback: compress_callback,
+            panic: None,
+        };
+
+        extern "C" fn compress_cb<F: FnMut(&[u8]) -> Result<(), ()>>(
+            context: *mut c_void,
+            data: *const c_void,
+            size: usize,
+        ) -> bool {
+            // SAFETY: This callback will only be called serially on a single thread. Both the
+            // panic state and the FnMut context need to be available mutably.
+            let cb_state = unsafe { context.cast::<CallbackState<F>>().as_mut() }.unwrap();
+            let data = unsafe { std::slice::from_raw_parts(data.cast(), size) };
+            let panic = std::panic::catch_unwind(AssertUnwindSafe(|| (cb_state.callback)(data)));
+            match panic {
+                Ok(r) => r.is_ok(),
+                Err(e) => {
+                    cb_state.panic = Some(e);
+                    false
+                }
+            }
+        }
+
+        let status = unsafe {
+            ffi::AndroidBitmap_compress(
+                &info.inner,
+                u32::from(data_space)
+                    .try_into()
+                    .expect("i32 overflow in DataSpace"),
+                pixels,
+                format as i32,
+                quality,
+                <*mut _>::cast(&mut cb_state),
+                Some(compress_cb::<F>),
+            )
+        };
+
+        if let Some(panic) = cb_state.panic {
+            std::panic::resume_unwind(panic)
+        }
+
+        Ok(BitmapError::from_status(status)?)
+    }
 }
 
 /// Possible values for [`ffi::ANDROID_BITMAP_FLAGS_ALPHA_MASK`] within [`BitmapInfoFlags`]
@@ -240,6 +376,34 @@ impl std::fmt::Debug for BitmapInfo {
 }
 
 impl BitmapInfo {
+    pub fn new(width: u32, height: u32, stride: u32, format: BitmapFormat) -> Self {
+        Self {
+            inner: ffi::AndroidBitmapInfo {
+                width,
+                height,
+                stride,
+                format: u32::from(format) as i32,
+                flags: 0,
+            },
+        }
+    }
+
+    #[cfg(feature = "api-level-30")]
+    pub fn new_with_flags(
+        width: u32,
+        height: u32,
+        stride: u32,
+        format: BitmapFormat,
+        flags: BitmapInfoFlags,
+    ) -> Self {
+        Self {
+            inner: ffi::AndroidBitmapInfo {
+                flags: flags.0,
+                ..Self::new(width, height, stride, format).inner
+            },
+        }
+    }
+
     /// The bitmap width in pixels.
     pub fn width(&self) -> u32 {
         self.inner.width
@@ -280,3 +444,51 @@ impl BitmapInfo {
         BitmapInfoFlags(self.inner.flags)
     }
 }
+
+/// Specifies the formats that can be compressed to with [`Bitmap::compress()`] and
+/// [`Bitmap::compress_raw()`].
+#[cfg(feature = "api-level-30")]
+#[repr(u32)]
+#[derive(Clone, Copy, Debug, Hash, PartialEq, Eq, TryFromPrimitive, IntoPrimitive)]
+#[doc(alias = "AndroidBitmapCompressFormat")]
+pub enum BitmapCompressFormat {
+    /// Compress to the JPEG format.
+    ///
+    /// quality of `0` means compress for the smallest size. `100` means compress for max visual
+    /// quality.
+    #[doc(alias = "ANDROID_BITMAP_COMPRESS_FORMAT_JPEG")]
+    Jpeg = ffi::AndroidBitmapCompressFormat::ANDROID_BITMAP_COMPRESS_FORMAT_JPEG.0,
+    /// Compress to the PNG format.
+    ///
+    /// PNG is lossless, so quality is ignored.
+    #[doc(alias = "ANDROID_BITMAP_COMPRESS_FORMAT_PNG")]
+    Png = ffi::AndroidBitmapCompressFormat::ANDROID_BITMAP_COMPRESS_FORMAT_PNG.0,
+    /// Compress to the WEBP lossless format.
+    ///
+    /// quality refers to how much effort to put into compression. A value of `0` means to
+    /// compress quickly, resulting in a relatively large file size. `100` means to spend more time
+    /// compressing, resulting in a smaller file.
+    #[doc(alias = "ANDROID_BITMAP_COMPRESS_FORMAT_WEBP_LOSSY")]
+    WebPLossy = ffi::AndroidBitmapCompressFormat::ANDROID_BITMAP_COMPRESS_FORMAT_WEBP_LOSSY.0,
+    /// Compress to the WEBP lossy format.
+    ///
+    /// quality of `0` means compress for the smallest size. `100` means compress for max visual quality.
+    #[doc(alias = "ANDROID_BITMAP_COMPRESS_FORMAT_WEBP_LOSSLESS")]
+    WebPLossless = ffi::AndroidBitmapCompressFormat::ANDROID_BITMAP_COMPRESS_FORMAT_WEBP_LOSSLESS.0,
+}
+
+/// Encapsulates possible errors returned by [`Bitmap::compress()`] or [`Bitmap::compress_raw()`].
+#[derive(Debug, Error)]
+pub enum BitmapCompressError {
+    #[error(transparent)]
+    BitmapError(#[from] BitmapError),
+    /// Only returned when [`Bitmap::compress()`] fails to read a valid [`DataSpace`] via
+    /// [`Bitmap::data_space()`].
+    #[error(transparent)]
+    DataSpaceFromPrimitiveError(#[from] TryFromPrimitiveError<DataSpace>),
+    /// [`Bitmap`] compression requires a known [`DataSpace`].  [`DataSpace::Unknown`] is invalid
+    /// even though it is typically treated as `sRGB`, for that [`DataSpace::Srgb`] has to be passed
+    /// explicitly.
+    #[error("The dataspace for this Bitmap is Unknown")]
+    DataSpaceUnknown,
+}