Sampling along the diagonal edge from (345, 275) to (577, 638):
t=0: (346, 277) -> R=135, G=111, B=67
t=0.1: (369, 313) -> R=230, G=227, B=222
t=0.2: (392, 349) -> R=239, G=238, B=234
t=0.3: (415, 385) -> R=241, G=240, B=236
t=0.4: (438, 421) -> R=241, G=240, B=236
t=0.5: (462, 458) -> R=240, G=239, B=235
t=0.6: (485, 494) -> R=202, G=175, B=122
t=0.7: (508, 530) -> R=219, G=185, B=113
t=0.8: (531, 566) -> R=186, G=148, B=77
t=0.9: (554, 602) -> R=152, G=112, B=50
t=1: (577, 638) -> R=133, G=107, B=70