Calibrate Brīdinājumi projection to validated city pixel positions

web/src/pages/warnings/warningDraw.ts

@@ -83,8 +83,8 @@ function drawWarning(ctx: CanvasRenderingContext2D, template: WarningTemplate, w
 function project(template: WarningTemplate, point: WarningPoint) {
     const { geo } = template;
     return {
-        x: geo.left + (point.lon - geo.west) / (geo.east - geo.west) * (geo.right - geo.left),
+        x: geo.a * point.lon + geo.b * point.lat + geo.c,
-        y: geo.top + (geo.north - point.lat) / (geo.north - geo.south) * (geo.bottom - geo.top),
+        y: geo.d * point.lon + geo.e * point.lat + geo.f,
     };
 }
 

web/src/pages/warnings/warningTemplates.ts

@@ -11,13 +11,19 @@ export type WarningTemplate = {
     map: string;
     border: string;
     feather: number;
-    geo: { west: number; east: number; north: number; south: number; left: number; right: number; top: number; bottom: number };
+    geo: { a: number; b: number; c: number; d: number; e: number; f: number };
     title: { right: number; top: number; height: number; fontSize: number; horizontalPadding: number; maximumWidth: number };
     legend: { right: number; bottom: number; swatch: number; gap: number; fontSize: number };
 };
 
-// The two newsroom canvases have independent crops. These pixel bounds align
+// `geo` maps (lon, lat) to pixel space as x = a*lon + b*lat + c, y = d*lon + e*lat + f.
-// Latvia's geographic extent to the white country outline in each source map.
+// The prior release used a 4-corner bounding-box stretch, which cannot represent
+// the source artwork's rotation/shear and drifted up to ~200px on the 3840 canvas
+// away from the calibration corners. These coefficients are a least-squares affine
+// fit of ~17 well-spread cities' real-world coordinates against the pixel positions
+// already validated for these same map_1920x1080/map_3840x1440 backgrounds by
+// Kartes/Faktiska (see cityCoords.ts + mapConsts.ts), and land within ~35px of
+// those validated positions on the 3840 canvas (~15px on 1920).
 export const warningTemplates: Record<WarningOutput, WarningTemplate> = {
     '1920x1080': {
         width: 1920,
@@ -25,7 +31,7 @@ export const warningTemplates: Record<WarningOutput, WarningTemplate> = {
         map: map1920,
         border: border1920,
         feather: 16,
-        geo: { west: 20.97, east: 28.24, north: 58.09, south: 55.67, left: 360, right: 1655, top: 115, bottom: 864 },
+        geo: { a: 171.6971, b: -21.1156, c: -2040.5772, d: -5.3027, e: -306.1028, f: 18050.1672 },
         title: { right: 88, top: 38, height: 62, fontSize: 30, horizontalPadding: 24, maximumWidth: 900 },
         legend: { right: 88, bottom: 58, swatch: 27, gap: 14, fontSize: 20 },
     },
@@ -35,7 +41,7 @@ export const warningTemplates: Record<WarningOutput, WarningTemplate> = {
         map: map3840,
         border: border3840,
         feather: 28,
-        geo: { west: 20.97, east: 28.24, north: 58.09, south: 55.67, left: 985, right: 3150, top: 80, bottom: 1400 },
+        geo: { a: 279.8026, b: -34.4106, c: -2997.9777, d: -8.6414, e: -498.8342, f: 29339.5317 },
         title: { right: 376, top: 76, height: 124, fontSize: 60, horizontalPadding: 48, maximumWidth: 1700 },
         legend: { right: 376, bottom: 76, swatch: 42, gap: 22, fontSize: 30 },
     },