lv_img_conf: improvements from code review

src/resources/lv_img_conv.py

@@ -107,10 +107,7 @@ def main():
             for x in range(img_width):
                 i = (y*img_width + x)*4 # buffer-index
                 pixel = img.getpixel((x,y))
-                r = pixel[0]
-                g = pixel[1]
-                b = pixel[2]
-                a = pixel[3]
+                r, g, b, a = pixel
                 buf[i + 0] = r
                 buf[i + 1] = g
                 buf[i + 2] = b
@@ -126,12 +123,9 @@ def main():
                 g_act = classify_pixel(pixel[1], 6)
                 b_act = classify_pixel(pixel[2], 5)
                 a = pixel[3]
-                if r_act > 0xF8:
-                    r_act = 0xF8
-                if g_act > 0xFC:
-                    g_act = 0xFC
-                if b_act > 0xF8:
-                    b_act = 0xF8
+                r_act = min(r_act, 0xF8)
+                g_act = min(g_act, 0xFC)
+                b_act = min(b_act, 0xF8)
                 c16 = ((r_act) << 8) | ((g_act) << 3) | ((b_act) >> 3) # RGR565
                 buf[i + 0] = (c16 >> 8) & 0xFF
                 buf[i + 1] = c16 & 0xFF
@@ -148,17 +142,15 @@ def main():
             for x in range(img_width):
                 c, a = img.getpixel((x,y))
                 p = w * y + (x >> 3) + 8  # +8 for the palette
-                #if(!isset(this.d_out[p])) this.d_out[p] = 0  # Clear the bits first
                 buf[p] |= (c & 0x1) << (7 - (x & 0x7))
-        # write palette information
-        palette_size = 2
-        bits_per_value = 1
+        # write palette information, for indexed-1-bit we need palette with two values
         # write 8 palette bytes
         buf[0] = 0
         buf[1] = 0
         buf[2] = 0
         buf[3] = 0
         # Normally there is much math behind this, but for the current use case this is close enough
+        # only needs to be more complicated if we have more than 2 colors in the palette
         buf[4] = 255
         buf[5] = 255
         buf[6] = 255