V2.0.0 - Rasterix - photo papers

2026-04-01 17:52:25 +02:00
parent ab01da5cbf
commit bb3ca6c871
3 changed files with 141 additions and 6 deletions
@@ -0,0 +1,95 @@
+import numpy as np
+from PIL import Image
+
+
+PAPER_PRESETS = {
+    "BN (ISO R 130, soft)": {"contrast": 0.88, "toe": 0.10, "shoulder": 0.04},
+    "B (ISO R 110, medium-soft)": {"contrast": 0.96, "toe": 0.08, "shoulder": 0.05},
+    "N (ISO R 90, normal)": {"contrast": 1.04, "toe": 0.06, "shoulder": 0.06},
+    "H (ISO R 70, hard)": {"contrast": 1.18, "toe": 0.05, "shoulder": 0.08},
+    "HD (ISO R 50, extra hard)": {"contrast": 1.32, "toe": 0.03, "shoulder": 0.10},
+    "Grade 00 (very soft)": {"contrast": 0.84, "toe": 0.12, "shoulder": 0.04},
+    "Grade 0 (soft)": {"contrast": 0.92, "toe": 0.09, "shoulder": 0.05},
+    "Grade 2 (normal)": {"contrast": 1.00, "toe": 0.07, "shoulder": 0.06},
+    "Grade 3 (normal-hard)": {"contrast": 1.12, "toe": 0.06, "shoulder": 0.07},
+    "Grade 4 (hard)": {"contrast": 1.24, "toe": 0.05, "shoulder": 0.09},
+    "Grade 5 (ultra hard)": {"contrast": 1.36, "toe": 0.03, "shoulder": 0.12},
+}
+
+
+def _apply_tone_curve(x, contrast, toe, shoulder):
+    x = np.clip(0.5 + (x - 0.5) * contrast, 0.0, 1.0)
+    if toe > 0:
+        x = x * (1.0 - toe) + np.power(x, 1.25) * toe
+    if shoulder > 0:
+        inv = 1.0 - x
+        x = 1.0 - (inv * (1.0 - shoulder) + np.power(inv, 1.25) * shoulder)
+    return np.clip(x, 0.0, 1.0)
+
+
+def _apply_paper_expiration(arr, years):
+    out = arr.copy()
+
+    fog = np.clip(years * 0.006, 0, 0.18)
+    out = out + fog * (1.0 - out)
+
+    blue_fade = np.clip(1.0 - (years * 0.012), 0.65, 1.0)
+    out[..., 2] *= blue_fade
+
+    contrast = np.clip(1.0 - (years * 0.01), 0.7, 1.0)
+    out = np.clip((out - 0.5) * contrast + 0.5, 0.0, 1.0)
+
+    return out
+
+
+def img_photo_paper(
+    image: Image.Image,
+    paper_type: str = "N (ISO R 90, normal)",
+    color_paper: bool = False,
+    paper_base: str = "RC",
+    paper_intensity: float = 100.0,
+    expiration_years: float = 0.0,
+) -> Image.Image:
+    src = np.asarray(image.convert("RGB"), dtype=np.float32) / 255.0
+    preset = PAPER_PRESETS.get(paper_type, PAPER_PRESETS["N (ISO R 90, normal)"])
+
+    contrast = preset["contrast"]
+    toe = preset["toe"]
+    shoulder = preset["shoulder"]
+
+    if paper_base == "FB":
+        toe += 0.02
+        shoulder += 0.01
+        contrast *= 0.98
+    elif paper_base == "RC":
+        contrast *= 1.02
+
+    intensity = float(np.clip(paper_intensity, 0.0, 200.0))
+    strength = (intensity - 100.0) / 100.0
+    contrast = np.clip(contrast * (1.0 + 0.25 * strength), 0.5, 2.5)
+    toe = np.clip(toe * (1.0 + 0.35 * strength), 0.0, 0.35)
+    shoulder = np.clip(shoulder * (1.0 + 0.35 * strength), 0.0, 0.35)
+
+    if color_paper:
+        out = _apply_tone_curve(src, contrast, toe, shoulder)
+        sat = 1.02 if paper_base == "RC" else 0.98
+        mean = out.mean(axis=2, keepdims=True)
+        out = np.clip(mean + (out - mean) * sat, 0.0, 1.0)
+    else:
+        # In B&W mode, force grayscale source before blending to avoid color casts
+        # at any intensity value (including > 100).
+        luma = 0.299 * src[..., 0] + 0.587 * src[..., 1] + 0.114 * src[..., 2]
+        src = np.stack([luma, luma, luma], axis=-1)
+        tone = _apply_tone_curve(luma, contrast, toe, shoulder)
+        out = np.stack([tone, tone, tone], axis=-1)
+
+    out = _apply_paper_expiration(out, expiration_years)
+
+    if intensity <= 100.0:
+        amount = (intensity / 100.0) * 0.90
+    else:
+        amount = 1.0 + ((intensity - 100.0) / 100.0) * 1.10
+    amount = np.clip(amount, 0.0, 2.0)
+
+    blended = np.clip(src + (out - src) * amount, 0.0, 1.0)
+    return Image.fromarray((blended * 255.0).astype(np.uint8), mode="RGB")