add an option for img2img background color

modules/images.py

@@ -622,3 +622,14 @@ def image_data(data):
         pass
 
     return '', None
+
+
+def flatten(img, bgcolor):
+    """replaces transparency with bgcolor (example: "#ffffff"), returning an RGB mode image with no transparency"""
+
+    if img.mode == "RGBA":
+        background = Image.new('RGBA', img.size, bgcolor)
+        background.paste(img, mask=img)
+        img = background
+
+    return img.convert('RGB')

modules/processing.py

@@ -832,7 +832,7 @@ class StableDiffusionProcessingImg2Img(StableDiffusionProcessing):
             self.color_corrections = []
         imgs = []
         for img in self.init_images:
-            image = img.convert("RGB")
+            image = images.flatten(img, opts.img2img_background_color)
 
             if crop_region is None:
                 image = images.resize_image(self.resize_mode, image, self.width, self.height)

modules/shared.py

@@ -363,6 +363,7 @@ options_templates.update(options_section(('sd', "Stable Diffusion"), {
     "initial_noise_multiplier": OptionInfo(1.0, "Noise multiplier for img2img", gr.Slider, {"minimum": 0.5, "maximum": 1.5, "step": 0.01 }),
     "img2img_color_correction": OptionInfo(False, "Apply color correction to img2img results to match original colors."),
     "img2img_fix_steps": OptionInfo(False, "With img2img, do exactly the amount of steps the slider specifies (normally you'd do less with less denoising)."),
+    "img2img_background_color": OptionInfo("#ffffff", "With img2img, fill image's transparent parts with this color.", gr.ColorPicker, {}),
     "enable_quantization": OptionInfo(False, "Enable quantization in K samplers for sharper and cleaner results. This may change existing seeds. Requires restart to apply."),
     "enable_emphasis": OptionInfo(True, "Emphasis: use (text) to make model pay more attention to text and [text] to make it pay less attention"),
     "use_old_emphasis_implementation": OptionInfo(False, "Use old emphasis implementation. Can be useful to reproduce old seeds."),

modules/ui.py

@@ -812,7 +812,7 @@ def create_ui():
 
                 with gr.Tabs(elem_id="mode_img2img") as tabs_img2img_mode:
                     with gr.TabItem('img2img', id='img2img'):
-                        init_img = gr.Image(label="Image for img2img", elem_id="img2img_image", show_label=False, source="upload", interactive=True, type="pil", tool=cmd_opts.gradio_img2img_tool).style(height=480)
+                        init_img = gr.Image(label="Image for img2img", elem_id="img2img_image", show_label=False, source="upload", interactive=True, type="pil", tool=cmd_opts.gradio_img2img_tool, image_mode="RGBA").style(height=480)
 
                     with gr.TabItem('Inpaint', id='inpaint'):
                         init_img_with_mask = gr.Image(label="Image for inpainting with mask", show_label=False, elem_id="img2maskimg", source="upload", interactive=True, type="pil", tool=cmd_opts.gradio_inpaint_tool, image_mode="RGBA").style(height=480)