# Heatmap Rendering Logic
Ptengine's attention heatmap determines colors based on relative user dwell time. Specifically, it uses the following formula and three rendering rules to determine the colors.
#### Attention Color Calculation Formula
Based on the formula above, areas exceeding 90% appear nearly red, then transition to orange, yellow, yellow-green, and blue, while areas at 0% are transparent.
**Three Rendering Rules**
1. **Attention converges toward the center of the browser viewport**
2. **Areas where users stop scrolling overlap and turn red**
3. **Colors are drawn based on the user's longest dwell position**
As an additional note, based on the above explanation, if a specific part of the page is viewed significantly more than other parts (e.g., the viewing time difference exceeds 10x), the colors for the rest of the page may become extremely faint. In this case, you can adjust the red threshold by moving the adjustment slider on the heatmap screen to the left, making the heatmap easier to read. Please feel free to use this feature.
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