fix: Remove incorrect delta from pixel factor calculation (#56)

* fix: Remove incorrect delta from pixel factor calculation * fix: Drawing factor calculation Co-authored-by: Christoph Pader <christoph@margelo.io>
margelo · Jan 23, 2023 · e327c9d · e327c9d
1 parent ed74ff4
commit e327c9d
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Showing 2 changed files with 6 additions and 6 deletions.
diff --git a/example/src/data/GraphData.ts b/example/src/data/GraphData.ts
@@ -11,7 +11,9 @@ export function generateRandomGraphData(length: number): GraphPoint[] {
   return Array<number>(length)
     .fill(0)
     .map((_, index) => ({
-      date: new Date(index),
+      date: new Date(
+        new Date(2000, 0, 1).getTime() + 1000 * 60 * 60 * 24 * index
+      ),
       value: weightedRandom(10, Math.pow(index + 1, 2)),
     }))
 }

diff --git a/src/CreateGraphPath.ts b/src/CreateGraphPath.ts
@@ -220,11 +220,9 @@ function createGraphPathBase({
 
     // Calculates how many points between two points must be
     // calculated and drawn onto the canvas
-    const drawingFactor = pixelFactorX(
-      new Date(point.date.getTime() - prev.date.getTime()),
-      range.x.min,
-      range.x.max
-    )
+    const spanX = range.x.max.getTime() - range.x.min.getTime()
+    const deltaX = point.date.getTime() - prev.date.getTime()
+    const drawingFactor = deltaX / spanX
     const drawingPixels = actualWidth * drawingFactor + horizontalPadding
     const numberOfDrawingPoints = Math.floor(drawingPixels / PIXEL_RATIO)