Add image adjustments pipeline (brightness, contrast, crop, effects)

pixstrip-core/src/operations/adjustments.rs

@@ -0,0 +1,198 @@
+use image::{DynamicImage, Rgba, RgbaImage};
+
+use crate::error::Result;
+use super::AdjustmentsConfig;
+
+pub fn apply_adjustments(
+    mut img: DynamicImage,
+    config: &AdjustmentsConfig,
+) -> Result<DynamicImage> {
+    // Crop to aspect ratio (before other adjustments)
+    if let Some((w_ratio, h_ratio)) = config.crop_aspect_ratio {
+        img = crop_to_aspect_ratio(img, w_ratio, h_ratio);
+    }
+
+    // Trim whitespace
+    if config.trim_whitespace {
+        img = trim_whitespace(img);
+    }
+
+    // Brightness
+    if config.brightness != 0 {
+        img = img.brighten(config.brightness);
+    }
+
+    // Contrast
+    if config.contrast != 0 {
+        img = img.adjust_contrast(config.contrast as f32);
+    }
+
+    // Saturation
+    if config.saturation != 0 {
+        img = adjust_saturation(img, config.saturation);
+    }
+
+    // Grayscale
+    if config.grayscale {
+        img = img.grayscale();
+    }
+
+    // Sepia
+    if config.sepia {
+        img = apply_sepia(img);
+    }
+
+    // Sharpen
+    if config.sharpen {
+        img = img.unsharpen(1.0, 5);
+    }
+
+    // Canvas padding
+    if config.canvas_padding > 0 {
+        img = add_canvas_padding(img, config.canvas_padding);
+    }
+
+    Ok(img)
+}
+
+fn crop_to_aspect_ratio(img: DynamicImage, w_ratio: f64, h_ratio: f64) -> DynamicImage {
+    let (iw, ih) = (img.width(), img.height());
+    let target_ratio = w_ratio / h_ratio;
+    let current_ratio = iw as f64 / ih as f64;
+
+    let (crop_w, crop_h) = if current_ratio > target_ratio {
+        // Image is wider than target, crop width
+        let new_w = (ih as f64 * target_ratio) as u32;
+        (new_w, ih)
+    } else {
+        // Image is taller than target, crop height
+        let new_h = (iw as f64 / target_ratio) as u32;
+        (iw, new_h)
+    };
+
+    let x = (iw - crop_w) / 2;
+    let y = (ih - crop_h) / 2;
+
+    img.crop_imm(x, y, crop_w, crop_h)
+}
+
+fn trim_whitespace(img: DynamicImage) -> DynamicImage {
+    let rgba = img.to_rgba8();
+    let (w, h) = (rgba.width(), rgba.height());
+
+    if w == 0 || h == 0 {
+        return img;
+    }
+
+    // Get corner pixel as reference background color
+    let bg = *rgba.get_pixel(0, 0);
+    let threshold = 30u32;
+
+    let is_bg = |p: &Rgba<u8>| -> bool {
+        let dr = (p[0] as i32 - bg[0] as i32).unsigned_abs();
+        let dg = (p[1] as i32 - bg[1] as i32).unsigned_abs();
+        let db = (p[2] as i32 - bg[2] as i32).unsigned_abs();
+        dr + dg + db < threshold
+    };
+
+    let mut top = 0u32;
+    let mut bottom = h - 1;
+    let mut left = 0u32;
+    let mut right = w - 1;
+
+    // Find top
+    'top: for y in 0..h {
+        for x in 0..w {
+            if !is_bg(rgba.get_pixel(x, y)) {
+                top = y;
+                break 'top;
+            }
+        }
+    }
+
+    // Find bottom
+    'bottom: for y in (0..h).rev() {
+        for x in 0..w {
+            if !is_bg(rgba.get_pixel(x, y)) {
+                bottom = y;
+                break 'bottom;
+            }
+        }
+    }
+
+    // Find left
+    'left: for x in 0..w {
+        for y in top..=bottom {
+            if !is_bg(rgba.get_pixel(x, y)) {
+                left = x;
+                break 'left;
+            }
+        }
+    }
+
+    // Find right
+    'right: for x in (0..w).rev() {
+        for y in top..=bottom {
+            if !is_bg(rgba.get_pixel(x, y)) {
+                right = x;
+                break 'right;
+            }
+        }
+    }
+
+    let crop_w = right.saturating_sub(left) + 1;
+    let crop_h = bottom.saturating_sub(top) + 1;
+
+    if crop_w == 0 || crop_h == 0 || (crop_w == w && crop_h == h) {
+        return img;
+    }
+
+    img.crop_imm(left, top, crop_w, crop_h)
+}
+
+fn adjust_saturation(img: DynamicImage, amount: i32) -> DynamicImage {
+    let mut rgba = img.into_rgba8();
+    let factor = 1.0 + (amount as f64 / 100.0);
+
+    for pixel in rgba.pixels_mut() {
+        let r = pixel[0] as f64;
+        let g = pixel[1] as f64;
+        let b = pixel[2] as f64;
+
+        let gray = 0.2126 * r + 0.7152 * g + 0.0722 * b;
+
+        pixel[0] = (gray + (r - gray) * factor).clamp(0.0, 255.0) as u8;
+        pixel[1] = (gray + (g - gray) * factor).clamp(0.0, 255.0) as u8;
+        pixel[2] = (gray + (b - gray) * factor).clamp(0.0, 255.0) as u8;
+    }
+
+    DynamicImage::ImageRgba8(rgba)
+}
+
+fn apply_sepia(img: DynamicImage) -> DynamicImage {
+    let mut rgba = img.into_rgba8();
+
+    for pixel in rgba.pixels_mut() {
+        let r = pixel[0] as f64;
+        let g = pixel[1] as f64;
+        let b = pixel[2] as f64;
+
+        pixel[0] = (0.393 * r + 0.769 * g + 0.189 * b).clamp(0.0, 255.0) as u8;
+        pixel[1] = (0.349 * r + 0.686 * g + 0.168 * b).clamp(0.0, 255.0) as u8;
+        pixel[2] = (0.272 * r + 0.534 * g + 0.131 * b).clamp(0.0, 255.0) as u8;
+    }
+
+    DynamicImage::ImageRgba8(rgba)
+}
+
+fn add_canvas_padding(img: DynamicImage, padding: u32) -> DynamicImage {
+    let (w, h) = (img.width(), img.height());
+    let new_w = w + padding * 2;
+    let new_h = h + padding * 2;
+
+    let mut canvas = RgbaImage::from_pixel(new_w, new_h, Rgba([255, 255, 255, 255]));
+
+    image::imageops::overlay(&mut canvas, &img.to_rgba8(), padding as i64, padding as i64);
+
+    DynamicImage::ImageRgba8(canvas)
+}