Menu
Surface.blit has a new parameter in 1.8: blend. The following values are defined:
BLEND_ADDBLEND_SUBBLEND_MULTBLEND_MINBLEND_MAXBLEND_RGBA_ADDBLEND_RGBA_SUBBLEND_RGBA_MULTBLEND_RGBA_MINBLEND_RGBA_MAXBLEND_RGB_ADDBLEND_RGB_SUBBLEND_RGB_MULTBLEND_RGB_MINBLEND_RGB_MAXCan someone explain what these modes mean?
733
What are blending modes? A blending mode is an effect you can add to a layer to change how the colors blend with colors on lower layers. You can change the look of your illustration simply by changing the blending modes.
A blending mode is a feature used to combine layers together. If you apply a blending mode to a layer it will affect how it interacts with all of the layers beneath it. If you are familiar with blending modes in Photoshop they work in the exact same way. It's kinda like having a colored filter.
Even though Photoshop includes 22 others, these five blend modes are the ones you'll use the most. The Multiply blend mode darkens images, the Screen blend mode lightens them, and the Overlay blend mode increases contrast. The Color blend mode blends only the color of a layer, and Luminosity blends only the brightness!
As the description implies, the difference blend mode subtracts the pixels of the base and blend layers and the result is the greater brightness value. Well, when you subtract two pixels with the same value, the result is black. This makes it very easy to see where images are aligned in Photoshop.
You can find the source for the blend operations here: surface.h
Basically, ADD adds the two source pixels and clips the result at 255. SUB subtracts the two pixels and clips at 0.
MULT: result = (p1 * p2) / 256
MIN: Select the lower value of each channel (not the whole pixel), so if pixel1 is (100,10,0) and pixel2 is (0,10,100), you get (0,10,0)
MAX: Opposite of MIN (i.e. (100,10,100))
And there is an additional blend mode which isn't obvious from the docs: 0 (or just leave the parameter out). This mode will "stamp" source surface into the destination. If the source surface has an alpha channel, this will be determine how "strong" each pixel is (0=no effect, 255=copy pixel, 128: result = .5*source + .5*destination).
Useful effects: To darken a certain area, use blend mode 0, fill the source/stamp surface black and set alpha to 10: (0,0,0,10).
To lighten it, use white (255,255,255,10).
198
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
