This commit is contained in:
Andrew Haynes
2026-03-04 21:59:41 -05:00
commit 7315d5005d
4 changed files with 296 additions and 0 deletions
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---
BasedOnStyle: Google
Standard: Latest
UseTab: Always
TabWidth: 8
IndentWidth: 8
BreakBeforeBraces: Allman
SpaceBeforeCpp11BracedList: true
SeparateDefinitionBlocks: Always
Cpp11BracedListStyle: false
BreakAfterReturnType: TopLevel
AlignTrailingComments:
Kind: Always
ReflowComments: Always
AllowShortFunctionsOnASingleLine: All
AllowShortIfStatementsOnASingleLine: AllIfsAndElse
AllowShortLoopsOnASingleLine: true
IndentAccessModifiers: false # Indent access specifiers by one level
AccessModifierOffset: -4 # Optional: adjust offset relative to the class indentation level
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build/
.cache/
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cmake_minimum_required(VERSION 3.16)
set(CMAKE_C_STANDARD 23)
set(CMAKE_C_STANDARD_REQUIRED ON)
set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
include_directories(include)
project(ppm_image_processor LANGUAGES C)
add_executable(ppm_image_processor src/main.c)
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#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
unsigned int
encoder(unsigned char r, unsigned char g, unsigned char b)
{
unsigned int color = 0;
color |= b << 0;
color |= g << 8;
color |= r << 16;
return color;
}
unsigned char
decoder(unsigned int clr, int byte)
{
if (byte == 1) return (clr & 0x000000FF) >> 0;
else if (byte == 2) return (clr & 0x0000FF00) >> 8;
else if (byte == 3) return (clr & 0x00FF0000) >> 16;
else if (byte == 4) return (clr & 0xFF000000) >> 24;
return 0;
}
// unsigned int
// decoder_int(unsigned int clr, int byte)
// {
// if (byte == 1) return (clr & 0x000000FF) >> 0;
// else if (byte == 2) return (clr & 0x0000FF00) >> 8;
// else if (byte == 3) return (clr & 0x00FF0000) >> 16;
// else if (byte == 4) return (clr & 0xFF000000) >> 24;
// return 0;
// }
unsigned int
set_alpha(unsigned int clr, unsigned char alpha_value)
{
return (clr & 0x00FFFFFF) | alpha_value << 24;
}
unsigned int
invert_rgb(unsigned int clr)
{
unsigned char alpha = (clr & 0xFF000000) >> 24;
return ((~clr) & 0x00FFFFFF) | alpha << 24;
}
unsigned int
swap_rb(unsigned int clr)
{
return (((clr & 0xFF00FF00) | ((decoder(clr, 3)) << 0) |
((decoder(clr, 1) >> 0) << 16)));
}
unsigned int
to_grayscale(unsigned int clr)
{
unsigned char alpha = decoder(clr, 4);
unsigned char red = decoder(clr, 3);
unsigned char green = decoder(clr, 2);
unsigned char blue = decoder(clr, 1);
int average = (red + green + blue) / 3;
unsigned int mask = encoder(average, average, average);
mask = set_alpha(mask, alpha);
return mask;
}
unsigned int
apply_threshold(unsigned int clr, unsigned char limit)
{
unsigned int mask = 0;
unsigned char average = decoder(to_grayscale(clr), 1);
if (average < limit) mask = encoder(0, 0, 0);
else mask = encoder(255, 255, 255);
mask = set_alpha(mask, decoder(clr, 4));
return mask;
}
unsigned int
adjust_brightness(unsigned int clr, float factor)
{
unsigned int red = decoder(clr, 3) * factor;
unsigned int green = decoder(clr, 2) * factor;
unsigned int blue = decoder(clr, 1) * factor;
if (red > 255) red = 255;
if (green > 255) green = 255;
if (blue > 255) blue = 255;
unsigned int mask = encoder(red, green, blue);
mask = set_alpha(mask, decoder(clr, 4));
return mask;
}
unsigned int
apply_tint(unsigned int clr_a, unsigned int clr_b)
{
unsigned char blue = (decoder(clr_a, 1) + decoder(clr_b, 1)) / 2;
unsigned char green = (decoder(clr_a, 2) + decoder(clr_b, 2)) / 2;
unsigned char red = (decoder(clr_a, 3) + decoder(clr_b, 3)) / 2;
return set_alpha(encoder(red, green, blue), decoder(clr_a, 4));
}
unsigned int
apply_opacity(unsigned clr_a, unsigned int clr_b, float ratio)
{
unsigned char blue =
(decoder(clr_a, 1) * (1 - ratio) + (decoder(clr_b, 1) * ratio));
unsigned char green =
(decoder(clr_a, 2) * (1 - ratio) + (decoder(clr_b, 2) * ratio));
unsigned char red =
(decoder(clr_a, 3) * (1 - ratio) + (decoder(clr_b, 3) * ratio));
return set_alpha(encoder(red, green, blue), decoder(clr_a, 4));
}
unsigned int*
ppm_encode(char* file, int* w, int* h, int* max_val, char* magic_number)
{
unsigned char r, g, b;
FILE* fptr;
fptr = fopen(file, "r");
if (!fptr) return NULL;
fscanf(fptr, "%s", magic_number);
fscanf(fptr, "%d %d", w, h);
fscanf(fptr, "%d", max_val);
unsigned int* buf = malloc((*w) * (*h) * sizeof(unsigned int));
if (!buf) return NULL;
for (int i = 0; i < (*w * *h); i++)
{
fscanf(fptr, "%hhu %hhu %hhu", &r, &g, &b);
unsigned int packed = encoder(r, g, b);
buf[i] = set_alpha(packed, 255);
}
fclose(fptr);
return buf;
}
void
ppm_apply_brightness(unsigned int* buf, int buf_size, float factor)
{
for (int i = 0; i < buf_size; i++)
{
buf[i] = adjust_brightness(buf[i], factor);
}
}
void
ppm_decode(unsigned int* buf, int buf_size, char* name, int* w, int* h)
{
unsigned char red, green, blue;
FILE* fptr = fopen(name, "w");
if (!fptr) return;
fprintf(fptr, "P3\n%d %d\n255\n", *w, *h);
for (int i = 0; i < buf_size; i++)
{
red = decoder(buf[i], 3);
green = decoder(buf[i], 2);
blue = decoder(buf[i], 1);
fprintf(fptr, "%d %d %d ", red, green, blue);
if ((i + 1) % *w == 0)
{
fprintf(fptr, "\n");
}
}
fclose(fptr);
}
unsigned int
channel_mask(unsigned int clr, char keep)
{
unsigned int mask = 0;
switch (keep)
{
case 'r':
mask = encoder(decoder(clr, 3), 0, 0);
break;
case 'g':
mask = encoder(0, decoder(clr, 2), 0);
break;
case 'b':
mask = encoder(0, 0, decoder(clr, 1));
break;
}
mask = set_alpha(mask, decoder(clr, 4));
return mask;
}
unsigned int
chromatic_circular_shift(unsigned int clr, int n)
{
unsigned int mask = 0;
unsigned char r, g, b;
r = decoder(clr, 3);
g = decoder(clr, 2);
b = decoder(clr, 1);
r = (r << n) | (r >> (8 - n));
g = (g << n) | (g >> (8 - n));
b = (b << n) | (b >> (8 - n));
mask = encoder(r, g, b);
mask = set_alpha(mask, decoder(clr, 4));
return mask;
}
unsigned int*
horizontal_flip(unsigned int* buf, int size, int w) {
}
unsigned int*
vertical_flip(unsigned int* buf, int size, int w, int h) {
}
void
print_bits_int(unsigned int n)
{
for (int i = 31; i >= 0; i--)
{
if (i == 7 || i == 15 || i == 23) write(1, " ", 1);
char bit = (n & (1 << i)) ? '1' : '0';
write(1, &bit, 1);
}
write(1, "\n", 1);
}
void
print_bits_char(unsigned char n)
{
for (int i = 7; i >= 0; i--)
{
char bit = (n & (1 << i)) ? '1' : '0';
write(1, &bit, 1);
}
write(1, "\n", 1);
}
int
main()
{
// unsigned int test = 40;
// print_bits_int(test);
// test = (test << 3) | (test >> (8 - 3));
// print_bits_int(test);
unsigned int color = encoder(200, 10, 50);
color = set_alpha(color, 100);
print_bits_int(color);
// unsigned int channelled_color = channel_mask(color, 'g');
color = chromatic_circular_shift(color, 3);
print_bits_int(color);
// int width, height;
// char magic_number[3];
// int max_val;
//
// unsigned int* buf =
// ppm_encode("../test.ppm", &width, &height, &max_val,
// magic_number);
// ppm_apply_brightness(buf, (width * height), .5);
// ppm_decode(buf, (width * height), "../new.ppm", &width, &height);
// free(buf);
return 0;
}