fix Int overflow on calculate rgb(....)
fix Int overflow on calculate rgb(....)

Alexey-T/CudaText,vhanla/CudaText,vhanla/CudaText,Alexey-T/CudaText,Alexey-T/CudaText,vhanla/CudaText,vhanla/CudaText,vhanla/CudaText,vhanla/CudaText,vhanla/CudaText,Alexey-T/CudaText,Alexey-T/CudaText,Alexey-T/CudaText,vhanla/CudaText,Alexey-T/CudaText,vhanla/CudaText,Alexey-T/CudaText,vhanla/CudaText