fix: lỗi áp dụng recipe lên live view của camera

src/utils/colorUtils.ts

@@ -1,45 +1,26 @@
-// Tanner Helland's Kelvin to RGB approximation
-// Kelvin range: 1000K to 40000K (we use 2500K to 10000K)
+// Kelvin to RGB compensation for White Balance.
+// In photography, when WB is set HIGH (e.g. 10000K), the camera understands
+// the scene light is COLD and compensates with WARM tones (red/orange).
+// When WB is set LOW (e.g. 2500K), the camera compensates with COOL tones (blue).
 export function kelvinToRGB(kelvin: number): { r: number; g: number; b: number } {
-  const temp = Math.max(1000, Math.min(40000, kelvin)) / 100;
-  let r = 0;
-  let g = 0;
-  let b = 0;
+  const k = Math.min(10000, Math.max(2500, kelvin));
+  let r = 1.0, g = 1.0, b = 1.0;
 
-  // Red
-  if (temp <= 66) {
-    r = 255;
+  if (k < 5500) {
+    // 2500K → 5500K: Warm light → need blue/cyan compensation
+    const factor = (5500 - k) / 3000;
+    r = 1.0 - factor * 0.45;
+    g = 1.0 - factor * 0.15;
+    b = 1.0 + factor * 0.50;
   } else {
-    r = temp - 60;
-    r = 329.698727446 * Math.pow(r, -0.1332047592);
-    r = Math.max(0, Math.min(255, r));
+    // 5500K → 10000K: Cool light → need warm/amber compensation
+    const factor = (k - 5500) / 4500;
+    r = 1.0 + factor * 0.55;
+    g = 1.0 + factor * 0.20;
+    b = 1.0 - factor * 0.40;
   }
 
-  // Green
-  if (temp <= 66) {
-    g = temp;
-    g = 99.4708025861 * Math.log(g) - 161.1195681661;
-    g = Math.max(0, Math.min(255, g));
-  } else {
-    g = temp - 60;
-    g = 288.1221695283 * Math.pow(g, -0.0755148492);
-    g = Math.max(0, Math.min(255, g));
-  }
-
-  // Blue
-  if (temp >= 66) {
-    b = 255;
-  } else {
-    if (temp <= 19) {
-      b = 0;
-    } else {
-      b = temp - 10;
-      b = 138.5177312231 * Math.log(b) - 305.0447927307;
-      b = Math.max(0, Math.min(255, b));
-    }
-  }
-
-  return { r: r / 255, g: g / 255, b: b / 255 };
+  return { r, g, b };
 }
 
 // Generate a 4x5 ColorMatrix (array of 20 floats) based on base style and adjustments
@@ -85,7 +66,7 @@ export function getSkiaColorMatrix(
       0, 0, 0, 1, 0,
     ];
   } else if (baseFilter === 'monochrome') {
-    // Classic black and white filter (luminance weights)
+    // Acros Monochrome: ITU-R BT.709 luma — pure grayscale, zero color leakage
     const r = 0.2126;
     const g = 0.7152;
     const b = 0.0722;
@@ -128,7 +109,10 @@ export function getSkiaColorMatrix(
     matrix = multiplyMatrices(chromeMat, matrix);
   }
 
-  // 5. White Balance (Kelvin Temperature and Tint)
+  // 5. White Balance (Kelvin Temperature and Tint) — skip for monochrome to prevent color leakage
+  if (baseFilter === 'monochrome') {
+    return matrix;
+  }
   const rgbTemp = kelvinToRGB(temperature);
   // Tint adjustment: -10 is Green (+G), +10 is Magenta (+R, +B)
   const tintR = tint > 0 ? (tint / 10) * 0.08 : 0;
@@ -159,6 +143,26 @@ export function getSkiaColorMatrix(
   return matrix;
 }
 
+// Compute a tint color + opacity from the matrix for camera overlay preview
+// Applies the matrix to white (1,1,1,1) to see what color cast the filter creates
+export function computeMatrixTint(matrix: number[]): { r: number; g: number; b: number; a: number } {
+  const apply = (r: number, g: number, b: number, a: number) => {
+    const row = (offset: number) =>
+      matrix[offset + 0] * r + matrix[offset + 1] * g + matrix[offset + 2] * b + matrix[offset + 3] * a + matrix[offset + 4];
+    return { r: row(0), g: row(5), b: row(10), a: row(15) };
+  };
+
+  // Apply matrix to neutral white to get the filter's color cast
+  const white = apply(1, 1, 1, 1);
+  // Clamp and compute perceived intensity to determine opacity
+  const clamp = (v: number) => Math.max(0, Math.min(1, v));
+  const intensity = (white.r + white.g + white.b) / 3;
+  // Opacity is higher when the filter deviates from neutral
+  const deviation = Math.abs(white.r - intensity) + Math.abs(white.g - intensity) + Math.abs(white.b - intensity);
+  const opacity = Math.min(0.35, deviation * 2.5);
+  return { r: clamp(white.r), g: clamp(white.g), b: clamp(white.b), a: opacity };
+}
+
 // 4x5 Matrix multiplication utility: A * B
 function multiplyMatrices(a: number[], b: number[]): number[] {
   const result = new Array(20).fill(0);

src/utils/locationUtils.ts

@@ -50,6 +50,18 @@ export async function getCurrentGPS(): Promise<GPSInfo | null> {
   }
 }
 
+export async function reverseGeocode(latitude: number, longitude: number): Promise<string | null> {
+  try {
+    const geo = await Location.reverseGeocodeAsync({ latitude, longitude });
+    if (geo && geo.length > 0) {
+      return (geo[0].subregion || geo[0].city || geo[0].region || '').toUpperCase() || null;
+    }
+  } catch (e) {
+    console.warn('Reverse geocode failed:', e);
+  }
+  return null;
+}
+
 export function formatCoordinate(val: number, type: 'lat' | 'lon'): string {
   const absolute = Math.abs(val);
   const degrees = Math.floor(absolute);