Commit f18dbfc for stable-diffusion.cpp

commit f18dbfced79d466329edb540adf5a86884423218
Author: Crystal Sight <admin@xway.ca>
Date:   Thu Oct 22 09:57:57 2026 -0500

    feat(server): allow recipes to override backend/params_backend in context (#2188)

diff --git a/examples/server/api.md b/examples/server/api.md
index bfa98f6..3ade7be 100644
--- a/examples/server/api.md
+++ b/examples/server/api.md
@@ -303,11 +303,15 @@ new model architectures.

 Optional `context` settings apply to each model load and override the matching
 startup setting. Supported fields are `vae_format` (`auto`, `flux`, `sd3`,
-`flux2`, or `wan`) and `model_args` (a string in the same format as
-`--model-args`; replaces the startup string). Other startup settings remain
-unchanged. Switching to a recipe that omits these fields restores the startup
-values. For example, PiD uses `{"vae_format": "flux"}` and Qwen Image Edit
-2511 uses `{"model_args": "qwen_image_zero_cond_t=true"}`.
+`flux2`, or `wan`), `model_args` (a string in the same format as
+`--model-args`; replaces the startup string), and `backend` / `params_backend`
+(strings in the same format as `--backend` / `--params-backend`; replace the
+startup assignments for that load, so a recipe can place components on
+specific devices, e.g. keep a large text encoder on CPU while another recipe
+uses the GPU). Other startup settings remain unchanged. Switching to a
+recipe that omits these fields restores the startup values. For example, PiD
+uses `{"vae_format": "flux"}` and Qwen Image Edit 2511 uses
+`{"model_args": "qwen_image_zero_cond_t=true"}`.

 Supported defaults:

diff --git a/examples/server/model_catalog.cpp b/examples/server/model_catalog.cpp
index e8a6414..8efe624 100644
--- a/examples/server/model_catalog.cpp
+++ b/examples/server/model_catalog.cpp
@@ -273,7 +273,7 @@ static void apply_recipe_defaults(const json& defaults, SDGenerationParams& para
 }

 static void apply_recipe_context(const json& settings, SDContextParams& params) {
-    check_keys(settings, {"vae_format", "model_args"});
+    check_keys(settings, {"vae_format", "model_args", "backend", "params_backend"});
     if (settings.contains("vae_format")) {
         const auto format = settings.at("vae_format").get<std::string>();
         if (format != "auto" && format != "flux" && format != "sd3" && format != "flux2" && format != "wan")
@@ -283,6 +283,12 @@ static void apply_recipe_context(const json& settings, SDContextParams& params)
     if (settings.contains("model_args")) {
         params.model_args = settings.at("model_args").get<std::string>();
     }
+    if (settings.contains("backend")) {
+        params.backend = settings.at("backend").get<std::string>();
+    }
+    if (settings.contains("params_backend")) {
+        params.params_backend = settings.at("params_backend").get<std::string>();
+    }
 }

 static const std::map<std::string, bool> k_recipe_features = {