/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at
http://mozilla.org/MPL/2.0/. */
use std::cell::UnsafeCell;
use std::mem::{size_of, zeroed};
use std::slice;
use winapi::ctypes::c_void;
use winapi::shared::windef::{HDC, RECT};
use winapi::um::dcommon::DWRITE_MEASURING_MODE;
use winapi::um::dwrite::IDWriteBitmapRenderTarget;
use winapi::um::dwrite::{DWRITE_GLYPH_OFFSET, DWRITE_GLYPH_RUN};
use winapi::um::wingdi::{GetCurrentObject, GetObjectW, BITMAP, OBJ_BITMAP, RGB};
use wio::com::ComPtr;
use super::{FontFace, RenderingParams};
pub struct BitmapRenderTarget {
native: UnsafeCell<ComPtr<IDWriteBitmapRenderTarget>>,
}
impl BitmapRenderTarget {
pub fn take(native: ComPtr<IDWriteBitmapRenderTarget>) -> BitmapRenderTarget {
BitmapRenderTarget {
native: UnsafeCell::new(native),
}
}
pub unsafe fn as_ptr(&self) -> *mut IDWriteBitmapRenderTarget {
(*self.native.get()).as_raw()
}
// A dip is 1/96th of an inch, so this value is the number of pixels per inch divided by 96.
pub fn set_pixels_per_dip(&self, ppd: f32) {
unsafe {
(*self.native.get()).SetPixelsPerDip(ppd);
}
}
pub fn get_memory_dc(&self) -> HDC {
unsafe { (*self.native.get()).GetMemoryDC() }
}
pub fn draw_glyph_run(
&self,
baseline_origin_x: f32,
baseline_origin_y: f32,
measuring_mode: DWRITE_MEASURING_MODE,
font_face: &FontFace,
em_size: f32,
glyph_indices: &[u16],
glyph_advances: &[f32],
glyph_offsets: &[DWRITE_GLYPH_OFFSET],
rendering_params: &RenderingParams,
color: &(f32, f32, f32),
) -> RECT {
unsafe {
assert!(glyph_indices.len() == glyph_advances.len());
assert!(glyph_indices.len() == glyph_offsets.len());
let r = (color.0 * 255.0) as u8;
let g = (color.1 * 255.0) as u8;
let b = (color.2 * 255.0) as u8;
let mut glyph_run: DWRITE_GLYPH_RUN = zeroed();
glyph_run.fontFace = font_face.as_ptr();
glyph_run.fontEmSize = em_size;
glyph_run.glyphCount = glyph_indices.len() as u32;
glyph_run.glyphIndices = glyph_indices.as_ptr();
glyph_run.glyphAdvances = glyph_advances.as_ptr();
glyph_run.glyphOffsets = glyph_offsets.as_ptr();
glyph_run.isSideways = 0;
glyph_run.bidiLevel = 0;
let mut rect: RECT = zeroed();
let hr = (*self.native.get()).DrawGlyphRun(
baseline_origin_x,
baseline_origin_y,
measuring_mode,
&glyph_run,
rendering_params.as_ptr(),
RGB(r, g, b),
&mut rect,
);
assert!(hr == 0);
rect
}
}
// This function expects to have glyphs rendered in WHITE,
// and pulls out a u8 vector of width*height*4 size with
// the coverage value (we pull out R) broadcast to the alpha
// channel, with the color white. That is, it performs:
// RGBX -> xxxR, where xxx = 0xff
pub fn get_opaque_values_as_mask(&self) -> Vec<u8> {
// Now grossness to pull out the pixels
unsafe {
let memory_dc = self.get_memory_dc();
let mut bitmap: BITMAP = zeroed();
let ret = GetObjectW(
GetCurrentObject(memory_dc, OBJ_BITMAP),
size_of::<BITMAP>() as i32,
&mut bitmap as *mut _ as *mut c_void,
);
assert!(ret == size_of::<BITMAP>() as i32);
assert!(bitmap.bmBitsPixel == 32);
let width = bitmap.bmWidth as usize;
let stride = bitmap.bmWidthBytes as usize;
let height = bitmap.bmHeight as usize;
let mut out_bytes: Vec<u8> = vec![0; width * height * 4];
let out_u32 =
slice::from_raw_parts_mut(out_bytes.as_mut_ptr() as *mut u32, width * height);
for row in 0..height {
let in_offset = (row * stride) as isize;
let in_u32 =
slice::from_raw_parts(bitmap.bmBits.offset(in_offset) as *const u32, width);
for col in 0..width {
let r = in_u32[col] & 0xff;
out_u32[width * row + col] = (r << 24) | (0x00ffffffu32);
}
}
out_bytes
}
}
}
