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// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <lib/fpromise/result.h>
#include "src/camera/lib/image_utils/image_writer.h"
namespace camera {
inline constexpr uint16_t kMaxVal = 4095;
inline constexpr uint16_t kRedPixel = 2048;
inline constexpr uint32_t kBytesPerDoublePixel = 3;
// Helper method that organizes two individual pixel values into the appropriate RAW12
// double-pixel format.
// Args:
// |first_pixel| A 12-bit value representing either a R or G pixel.
// |second_pixel| A 12-bit value representing either a G or B pixel.
// Returns:
// An array of the bytes that were passed in arranged in RAW12 pixel format.
std::array<uint8_t, kBytesPerDoublePixel> PixelValuesToDoublePixel(uint16_t first_pixel_val,
uint16_t second_pixel_val);
// Helper method that extracts the original pixel values from a RAW12 double-pixel.
// Args:
// |double_pixel| An array of bytes arranged in RAW12 pixel format (represents two pixels).
// Returns:
// A pair of each of the two 12-bit pixel values that comprised the original double-pixel.
std::pair<uint16_t, uint16_t> DoublePixelToPixelValues(
std::array<uint8_t, kBytesPerDoublePixel> double_pixel);
class Raw12Writer : public ImageWriter {
// Constructor.
// Args:
// |width| The width of the image to be written.
// |height| The height of the image to be written.
// |vmo_size| Number of bytes comprising the intended images to be written (width * height * # of
// bytes per pixel).
explicit Raw12Writer(uint32_t width, uint32_t height, size_t vmo_size)
: ImageWriter(width, height, vmo_size) {}
// Factory method that outputs a Raw12Writer with all its params set for the format.
// Args:
// |width| Intended width for images to be written (in # of pixels).
// |height| Intended height for images to be written (in # of pixels).
// |pixel_format| Intended byte representation for each pixel in the images to be written.
// Returns:
// A Raw12Writer object that writes images to vmos.
static fpromise::result<std::unique_ptr<Raw12Writer>, zx_status_t> Create(uint32_t width,
uint32_t height);
// Fills a provided vmo with default data in the RAW12 image format. Only a RGGB layout is used at
// the moment.
// The red pixel value stays consistent at a value of r throughout the image.
// The green pixels value increases from 0 to a maximum of g across individual rows.
// The blue pixel value increases from 0 to a maximum of b across individual columns.
// Each double-pixel is laid out like so:
// Bits -> 7 6 5 4 3 2 1 0
// Byte0 -> P0[11] P0[10] P0[9] P0[8] P0[7] P0[6] P0[5] P0[4]
// Byte1 -> P1[11] P1[10] P1[9] P1[8] P1[7] P1[6] P1[5] P1[4]
// Byte2 -> P1[3] P1[2] P1[1] P1[0] P0[3] P0[2] P0[1] P0[0]
// A RG row with two double-pixels (six bytes) looks like:
// R0[11:4], G0[11:4], G0[3:0]R0[3:0], R1[11:4], G1[11:4], G1[3:0]R1[3:0]
// A GB row with two double pixels (six bytes) looks like:
// G0[11:4], B0[11:4], B0[3:0]G0[3:0], G1[11:4], B1[11:4], B1[3:0]G1[3:0]
// Args:
// |vmo| Memory object handle to which the image will be written. The vmo must have been created
// before passing it in.
// |r| Red pixel value; default is set to kRedPixel.
// |g| Green pixel values in the image will range from 0 to g; default is set to kMaxPixelVal.
// |b| Blue pixel values in the image will range from 0 to b; default is set to kMaxPixelVal.
// TODO(nzo): split g into gr and gb.
// TODO(nzo): use a more straightforward filling method; scaling with step functions causes a few
// issues downstream of image creation.
zx_status_t Write(zx::vmo* vmo, uint16_t r, uint16_t g, uint16_t b) override;
} // namespace camera