簡介
當使用者選擇 S 號襯衫，然後將其更改為 XL 號，或從修身版更改為超大號時，設計必須自我調整。這不是簡單的比例問題，而是你必須了解上下文：如果設計有文字，文字必須仍然可讀，全正面設計必須相應擴大，左胸印花必須保持小比例。
1. 尺寸與形狀資料模型
@dataclass
class GarmentSpec:
size: str # XS, S, M, L, XL, 2XL, 3XL
form: str # slim, regular, oversize
chest_width_cm: float # Rộng ngực
body_length_cm: float # Dài thân áo
GARMENT_SPECS = {
# Size → Form → Measurements
("S", "slim"): GarmentSpec("S", "slim", 46, 68),
("S", "regular"): GarmentSpec("S", "regular", 48, 70),
("M", "slim"): GarmentSpec("M", "slim", 49, 71),
("M", "regular"): GarmentSpec("M", "regular", 51, 72),
("M", "oversize"): GarmentSpec("M", "oversize", 56, 74),
("L", "regular"): GarmentSpec("L", "regular", 54, 74),
("L", "oversize"): GarmentSpec("L", "oversize", 59, 76),
("XL", "regular"): GarmentSpec("XL", "regular", 57, 76),
("XL", "oversize"):GarmentSpec("XL", "oversize", 62, 78),
("2XL", "regular"):GarmentSpec("2XL", "regular", 60, 78),
("2XL", "oversize"):GarmentSpec("2XL", "oversize", 65, 80),
}
2. 擴充引擎
class DesignScaler:
"""Auto-scale design theo size và form áo"""
def scale_for_garment(
self,
design: Image.Image,
print_zone: str,
from_spec: GarmentSpec,
to_spec: GarmentSpec,
) -> Image.Image:
# Tính scale ratio
ratio = self._calculate_scale_ratio(
print_zone, from_spec, to_spec
)
if abs(ratio - 1.0) < 0.02:
return design # Không cần scale
# Scale với anti-aliasing
new_width = int(design.width * ratio)
new_height = int(design.height * ratio)
scaled = design.resize(
(new_width, new_height),
Image.Resampling.LANCZOS
)
# Verify quality after scaling
if ratio > 1.3: # Scale lên > 30%
scaled = self._upscale_ai(scaled) # Real-ESRGAN
return scaled
def _calculate_scale_ratio(
self,
print_zone: str,
from_spec: GarmentSpec,
to_spec: GarmentSpec,
) -> float:
if print_zone == "left_chest":
# Left chest: giữ nguyên kích thước tuyệt đối
return 1.0
elif print_zone == "front_chest":
# Front chest: scale theo tỷ lệ ngực
return to_spec.chest_width_cm / from_spec.chest_width_cm
elif print_zone == "full_front":
# Full front: scale theo cả width VÀ height
width_ratio = to_spec.chest_width_cm / from_spec.chest_width_cm
height_ratio = to_spec.body_length_cm / from_spec.body_length_cm
return (width_ratio + height_ratio) / 2
elif print_zone == "back_print":
return to_spec.chest_width_cm / from_spec.chest_width_cm
return 1.0
3. 內容感知縮放
class ContentAwareScaler:
"""Scale thông minh — giữ text readable, giữ tỷ lệ quan trọng"""
def smart_scale(
self,
design: Image.Image,
scale_ratio: float,
) -> Image.Image:
# Detect content type
has_text = self._detect_text(design)
has_faces = self._detect_faces(design)
if has_text and scale_ratio < 0.7:
# Text sẽ quá nhỏ → cảnh báo
return self._scale_with_text_preservation(
design, scale_ratio
)
if has_faces and scale_ratio != 1.0:
# Faces cần giữ tỷ lệ chính xác
return self._scale_face_aware(design, scale_ratio)
# Standard scaling
return self._standard_scale(design, scale_ratio)
def _scale_with_text_preservation(
self,
design: Image.Image,
ratio: float,
) -> Image.Image:
"""
Khi scale nhỏ lại, text có thể không đọc được.
Strategy: scale graphics nhưng giữ text size minimum.
"""
# Separate text layer và graphics layer
text_mask = self._segment_text(design)
graphics = self._remove_text(design, text_mask)
# Scale graphics theo ratio
scaled_graphics = graphics.resize(
(int(graphics.width * ratio),
int(graphics.height * ratio)),
Image.Resampling.LANCZOS,
)
# Text: scale nhưng enforce minimum size
min_text_ratio = max(ratio, 0.8)
scaled_text = self._scale_text_layer(
design, text_mask, min_text_ratio
)
# Composite
return self._composite(scaled_graphics, scaled_text)
4.DPI管理
class DPIManager:
"""Quản lý DPI khi scale design"""
MIN_PRINT_DPI = 150
OPTIMAL_PRINT_DPI = 300
def calculate_effective_dpi(
self,
design: Image.Image,
print_zone: PrintZone,
) -> float:
"""Tính DPI thực tế khi in"""
# DPI = pixels / inches
print_width_inches = print_zone.width_cm / 2.54
effective_dpi = design.width / print_width_inches
return round(effective_dpi, 1)
def needs_upscale(
self,
design: Image.Image,
print_zone: PrintZone,
) -> bool:
dpi = self.calculate_effective_dpi(design, print_zone)
return dpi < self.MIN_PRINT_DPI
def upscale_for_print(
self,
design: Image.Image,
target_dpi: int = 300,
print_zone: PrintZone = None,
) -> Image.Image:
"""Upscale design để đạt target DPI"""
current_dpi = self.calculate_effective_dpi(design, print_zone)
if current_dpi >= target_dpi:
return design
scale = target_dpi / current_dpi
if scale <= 2.0:
# Lanczos đủ tốt cho scale <= 2x
return design.resize(
(int(design.width * scale),
int(design.height * scale)),
Image.Resampling.LANCZOS,
)
else:
# Cần AI upscaling (Real-ESRGAN)
return self._ai_upscale(design, scale)
總結
自動縮放系統：
- 服裝規格 — 每個尺寸/款式的準確模型數據
- 縮放比例 — 每個列印區域的不同計算
- 內容感知 — 縮放時保持文字可讀、臉部比例
- DPI管理 — 當DPI不足以列印時自動放大
下一篇文章：人工智慧編輯助手 — 使用自然語言編輯設計。