text: /*
   * This file is part of the Micro Python project, http://micropython.org/
   *
   * The MIT License (MIT)
   *
   * Copyright (c) 2018 Scott Shawcroft for Adafruit Industries
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   * THE SOFTWARE.
   */
  
  #include "shared-bindings/displayio/Bitmap.h"
  
  #include <string.h>
  
  #include "py/runtime.h"
  
  void common_hal_displayio_bitmap_construct(displayio_bitmap_t *self, uint32_t width,
      uint32_t height, uint32_t bits_per_value) {
      uint32_t row_width = width * bits_per_value;
      // align to size_t
      uint8_t align_bits = 8 * sizeof(size_t);
      if (row_width % align_bits != 0) {
          self->stride = (row_width / align_bits + 1);
      } else {
          self->stride = row_width / align_bits;
      }
      self->width = width;
      self->height = height;
      self->data = m_malloc(self->stride * height * sizeof(size_t), false);
      self->read_only = false;
      self->bits_per_value = bits_per_value;
  
      if (bits_per_value > 8 && bits_per_value != 16 && bits_per_value != 32) {
          mp_raise_NotImplementedError(translate("Invalid bits per value"));
      }
  
      // Division and modulus can be slow because it has to handle any integer. We know bits_per_value
      // is a power of two. We divide and mod by bits_per_value to compute the offset into the byte
      // array. So, we can the offset computation to simplify to a shift for division and mask for mod.
  
      self->x_shift = 0; // Used to divide the index by the number of pixels per word. Its used in a
                         // shift which effectively divides by 2 ** x_shift.
      uint32_t power_of_two = 1;
      while (power_of_two < align_bits / bits_per_value ) {
          self->x_shift++;
          power_of_two <<= 1;
      }
      self->x_mask = (1 << self->x_shift) - 1; // Used as a modulus on the x value
      self->bitmask = (1 << bits_per_value) - 1;
  
      self->dirty_area.x1 = 0;
      self->dirty_area.x2 = width;
      self->dirty_area.y1 = 0;
      self->dirty_area.y2 = height;
  }
  
  uint16_t common_hal_displayio_bitmap_get_height(displayio_bitmap_t *self) {
      return self->height;
  }
  
  uint16_t common_hal_displayio_bitmap_get_width(displayio_bitmap_t *self) {
      return self->width;
  }
  
  uint32_t common_hal_displayio_bitmap_get_bits_per_value(displayio_bitmap_t *self) {
      return self->bits_per_value;
  }
  
  uint32_t common_hal_displayio_bitmap_get_pixel(displayio_bitmap_t *self, int16_t x, int16_t y) {
      if (x >= self->width || x < 0 || y >= self->height || y < 0) {
          return 0;
      }
      int32_t row_start = y * self->stride;
      uint32_t bytes_per_value = self->bits_per_value / 8;
      if (bytes_per_value < 1) {
          size_t word = self->data[row_start + (x >> self->x_shift)];
  
          return (word >> (sizeof(size_t) * 8 - ((x & self->x_mask) + 1) * self->bits_per_value)) & self->bitmask;
      } else {
          size_t* row = self->data + row_start;
          if (bytes_per_value == 1) {
              return ((uint8_t*) row)[x];
          } else if (bytes_per_value == 2) {
              return ((uint16_t*) row)[x];
          } else if (bytes_per_value == 4) {
              return ((uint32_t*) row)[x];
          }
      }
      return 0;
  }
  
  void common_hal_displayio_bitmap_blit(displayio_bitmap_t *self, int16_t x, int16_t y, displayio_bitmap_t *source,
                              int16_t x1, int16_t y1, int16_t x2, int16_t y2, uint32_t skip_index, bool skip_index_none) {
      // Copy complete "source" bitmap into "self" bitmap at location x,y in the "self"
      // Add a boolean to determine if all values are copied, or only if non-zero
      // If skip_value is encountered in the source bitmap, it will not be copied.
      // If skip_value is `None`, then all pixels are copied.
  
      if (self->read_only) {
          mp_raise_RuntimeError(translate("Read-only object"));
      }
  
      // simplest version - use internal functions for get/set pixels
      for (int16_t i=0; i < (x2-x1) ; i++) {
          if ( (x+i >= 0) && (x+i < self->width) ) {
              for (int16_t j=0; j < (y2-y1) ; j++){
                  if ((y+j >= 0) && (y+j < self->height) ) {
                      uint32_t value = common_hal_displayio_bitmap_get_pixel(source, x1+i, y1+j);
                      if ( (skip_index_none) || (value != skip_index) ) { // write if skip_value_none is True
                              common_hal_displayio_bitmap_set_pixel(self, x+i, y+j, value);
                      }
                  }
              }
          }
      }
  }
  
  void common_hal_displayio_bitmap_set_pixel(displayio_bitmap_t *self, int16_t x, int16_t y, uint32_t value) {
      if (self->read_only) {
          mp_raise_RuntimeError(translate("Read-only object"));
      }
      // Update the dirty area.
      if (self->dirty_area.x1 == self->dirty_area.x2) {
          self->dirty_area.x1 = x;
          self->dirty_area.x2 = x + 1;
          self->dirty_area.y1 = y;
          self->dirty_area.y2 = y + 1;
      } else {
          if (x < self->dirty_area.x1) {
              self->dirty_area.x1 = x;
          } else if (x >= self->dirty_area.x2) {
              self->dirty_area.x2 = x + 1;
          }
          if (y < self->dirty_area.y1) {
              self->dirty_area.y1 = y;
          } else if (y >= self->dirty_area.y2) {
              self->dirty_area.y2 = y + 1;
          }
      }
  
      // Update our data
      int32_t row_start = y * self->stride;
      uint32_t bytes_per_value = self->bits_per_value / 8;
      if (bytes_per_value < 1) {
          uint32_t bit_position = (sizeof(size_t) * 8 - ((x & self->x_mask) + 1) * self->bits_per_value);
          uint32_t index = row_start + (x >> self->x_shift);
          uint32_t word = self->data[index];
          word &= ~(self->bitmask << bit_position);
          word |= (value & self->bitmask) << bit_position;
          self->data[index] = word;
      } else {
          size_t* row = self->data + row_start;
          if (bytes_per_value == 1) {
              ((uint8_t*) row)[x] = value;
          } else if (bytes_per_value == 2) {
              ((uint16_t*) row)[x] = value;
          } else if (bytes_per_value == 4) {
              ((uint32_t*) row)[x] = value;
          }
      }
  }
  
  displayio_area_t* displayio_bitmap_get_refresh_areas(displayio_bitmap_t *self, displayio_area_t* tail) {
      if (self->dirty_area.x1 == self->dirty_area.x2) {
          return tail;
      }
      self->dirty_area.next = tail;
      return &self->dirty_area;
  }
  
  void displayio_bitmap_finish_refresh(displayio_bitmap_t *self) {
      self->dirty_area.x1 = 0;
      self->dirty_area.x2 = 0;
  }
  
  void common_hal_displayio_bitmap_fill(displayio_bitmap_t *self, uint32_t value) {
      if (self->read_only) {
          mp_raise_RuntimeError(translate("Read-only object"));
      }
      // Update the dirty area.
      self->dirty_area.x1 = 0;
      self->dirty_area.x2 = self->width;
      self->dirty_area.y1 = 0;
      self->dirty_area.y2 = self->height;
  
      // build the packed word
      uint32_t word = 0;
      for (uint8_t i=0; i<32 / self->bits_per_value; i++) {
          word |= (value & self->bitmask) << (32 - ((i+1)*self->bits_per_value));
      }
      // copy it in
      for (uint32_t i=0; i<self->stride * self->height; i++) {
          self->data[i] = word;
      }
  }
  