Make new LATENT_PREVIEWER type for declaring KSampler preview methods

nodes.py

@@ -34,6 +34,11 @@ import importlib
 import folder_paths
 
 
+class LatentPreviewer:
+    def decode_latent_to_preview(self, device, x0):
+        pass
+
+
 def before_node_execution():
     comfy.model_management.throw_exception_if_processing_interrupted()
 
@@ -282,6 +287,27 @@ class TAESDEncode:
         samples = taesd.encoder(pixels.permute(0, 3, 1, 2).to(device)).to(device)
         return ({"samples": samples}, )
 
+class TAESDPreviewerImpl(LatentPreviewer):
+    def __init__(self, taesd):
+        self.taesd = taesd
+
+    def decode_latent_to_preview(self, device, x0):
+        x_sample = self.taesd.decoder(x0.to(device))[0].detach()
+        x_sample = self.taesd.unscale_latents(x_sample)  # returns value in [-2, 2]
+        x_sample = x_sample * 0.5
+        return x_sample
+
+class TAESDPreviewer:
+    @classmethod
+    def INPUT_TYPES(s):
+        return {"required": { "taesd": ("TAESD", ), }}
+    RETURN_TYPES = ("LATENT_PREVIEWER",)
+    FUNCTION = "make_previewer"
+
+    CATEGORY = "latent/previewer"
+
+    def make_previewer(self, taesd):
+        return (TAESDPreviewerImpl(taesd), )
 
 class SaveLatent:
     def __init__(self):
@@ -986,10 +1012,8 @@ class SetLatentNoiseMask:
         return (s,)
 
 
-def decode_latent_to_preview_image(taesd, device, preview_format, x0):
+def decode_latent_to_preview_image(previewer, device, preview_format, x0):
-    x_sample = taesd.decoder(x0.to(device))[0].detach()
+    x_sample = previewer.decode_latent_to_preview(device, x0)
-    x_sample = taesd.unscale_latents(x_sample)  # returns value in [-2, 2]
-    x_sample = x_sample * 0.5
 
     x_sample = torch.clamp((x_sample + 1.0) / 2.0, min=0.0, max=1.0)
     x_sample = 255. * np.moveaxis(x_sample.cpu().numpy(), 0, 2)
@@ -1015,7 +1039,7 @@ def decode_latent_to_preview_image(taesd, device, preview_format, x0):
     return preview_bytes
 
 
-def common_ksampler(model, seed, steps, cfg, sampler_name, scheduler, positive, negative, latent, denoise=1.0, disable_noise=False, start_step=None, last_step=None, force_full_denoise=False, taesd=None):
+def common_ksampler(model, seed, steps, cfg, sampler_name, scheduler, positive, negative, latent, denoise=1.0, disable_noise=False, start_step=None, last_step=None, force_full_denoise=False, previewer=None):
     device = comfy.model_management.get_torch_device()
     latent_image = latent["samples"]
 
@@ -1036,8 +1060,8 @@ def common_ksampler(model, seed, steps, cfg, sampler_name, scheduler, positive,
     pbar = comfy.utils.ProgressBar(steps)
     def callback(step, x0, x, total_steps):
         preview_bytes = None
-        if taesd:
+        if previewer:
-            preview_bytes = decode_latent_to_preview_image(taesd, device, preview_format, x0)
+            preview_bytes = decode_latent_to_preview_image(previewer, device, preview_format, x0)
         pbar.update_absolute(step + 1, total_steps, preview_bytes)
 
     samples = comfy.sample.sample(model, noise, steps, cfg, sampler_name, scheduler, positive, negative, latent_image,
@@ -1063,7 +1087,7 @@ class KSampler:
                     "denoise": ("FLOAT", {"default": 1.0, "min": 0.0, "max": 1.0, "step": 0.01}),
                      },
                 "optional": {
-                    "taesd": ("TAESD",)
+                    "previewer": ("LATENT_PREVIEWER",)
                 }}
 
     RETURN_TYPES = ("LATENT",)
@@ -1071,8 +1095,8 @@ class KSampler:
 
     CATEGORY = "sampling"
 
-    def sample(self, model, seed, steps, cfg, sampler_name, scheduler, positive, negative, latent_image, denoise=1.0, taesd=None):
+    def sample(self, model, seed, steps, cfg, sampler_name, scheduler, positive, negative, latent_image, denoise=1.0, previewer=None):
-        return common_ksampler(model, seed, steps, cfg, sampler_name, scheduler, positive, negative, latent_image, denoise=denoise, taesd=taesd)
+        return common_ksampler(model, seed, steps, cfg, sampler_name, scheduler, positive, negative, latent_image, denoise=denoise, previewer=previewer)
 
 class KSamplerAdvanced:
     @classmethod
@@ -1093,7 +1117,7 @@ class KSamplerAdvanced:
                     "return_with_leftover_noise": (["disable", "enable"], ),
                      },
                 "optional": {
-                    "taesd": ("TAESD",)
+                    "previewer": ("LATENT_PREVIEWER",)
                 }}
 
     RETURN_TYPES = ("LATENT",)
@@ -1101,14 +1125,14 @@ class KSamplerAdvanced:
 
     CATEGORY = "sampling"
 
-    def sample(self, model, add_noise, noise_seed, steps, cfg, sampler_name, scheduler, positive, negative, latent_image, start_at_step, end_at_step, return_with_leftover_noise, denoise=1.0, taesd=None):
+    def sample(self, model, add_noise, noise_seed, steps, cfg, sampler_name, scheduler, positive, negative, latent_image, start_at_step, end_at_step, return_with_leftover_noise, denoise=1.0, previewer=None):
         force_full_denoise = True
         if return_with_leftover_noise == "enable":
             force_full_denoise = False
         disable_noise = False
         if add_noise == "disable":
             disable_noise = True
-        return common_ksampler(model, noise_seed, steps, cfg, sampler_name, scheduler, positive, negative, latent_image, denoise=denoise, disable_noise=disable_noise, start_step=start_at_step, last_step=end_at_step, force_full_denoise=force_full_denoise, taesd=taesd)
+        return common_ksampler(model, noise_seed, steps, cfg, sampler_name, scheduler, positive, negative, latent_image, denoise=denoise, disable_noise=disable_noise, start_step=start_at_step, last_step=end_at_step, force_full_denoise=force_full_denoise, previewer=previewer)
 
 class SaveImage:
     def __init__(self):
@@ -1369,6 +1393,7 @@ NODE_CLASS_MAPPINGS = {
     "VAELoader": VAELoader,
     "TAESDDecode": TAESDDecode,
     "TAESDEncode": TAESDEncode,
+    "TAESDPreviewer": TAESDPreviewer,
     "TAESDLoader": TAESDLoader,
     "EmptyLatentImage": EmptyLatentImage,
     "LatentUpscale": LatentUpscale,
@@ -1425,6 +1450,7 @@ NODE_DISPLAY_NAME_MAPPINGS = {
     "CheckpointLoaderSimple": "Load Checkpoint",
     "VAELoader": "Load VAE",
     "TAESDLoader": "Load TAESD",
+    "TAESDPreviewer": "TAESD Previewer",
     "LoraLoader": "Load LoRA",
     "CLIPLoader": "Load CLIP",
     "ControlNetLoader": "Load ControlNet Model",