I am doing an Android Project. I have area of the image in pixel per unit. How can I convert that to square inches
I have tested the conversion of unit in one particular image. I have used this particular formula for conversion in Java.
float inchesWidth = (float) width / dpi;
float inchesHeight = (float) height / dpi;
float areaInSquareInches = inchesWidth * inchesHeight;
Suppose the Width of the image is 678. The height of the image is 452. The dpi of the Android device is 440. I am getting area = 1.58 square inches. Can anyone confirm me that I am using right formula and right method because there is no way to confirm this.
Assuming you're not scaling the image at all, your math is right. If you're scaling, you need to multiply by the scale factor (and the x and y scale factors can be independent, although generally they are the same). You also have to make sure you're using the right dpi- you want to use the logical dpi of the running OS, not the native dpi of the physical device (some devices might have a physical dpi of say 300 pixels per inch, but the OS will pretend its some smaller number (say 250) to provide some magnification).