sd_txt2img_highres: High-resolution image generation via patch-based pipeline

In sd2R: Stable Diffusion Image Generation

High-resolution image generation via patch-based pipeline

Description

Generates a large image by independently rendering overlapping patches at the model's native resolution, then stitching them with linear blending. An optional img2img harmonization pass can smooth seams further.

Usage

sd_txt2img_highres(
  ctx,
  prompt,
  negative_prompt = "",
  width = 2048L,
  height = 2048L,
  tile_size = NULL,
  overlap = 0.125,
  img2img_strength = NULL,
  sample_method = SAMPLE_METHOD$EULER,
  sample_steps = 20L,
  cfg_scale = 7,
  seed = 42L,
  scheduler = SCHEDULER$DISCRETE,
  clip_skip = -1L,
  eta = 0,
  vae_mode = "auto",
  vae_auto_threshold = 1048576L,
  vae_tile_size = 64L,
  vae_tile_overlap = 0.25
)

Arguments

ctx	SD context created by sd_ctx
prompt	Text prompt
negative_prompt	Negative prompt (default "")
width	Target image width in pixels
height	Target image height in pixels
tile_size	Patch size in pixels. NULL = auto-detect from model_type attribute on ctx (512 for SD1/SD2, 1024 for SDXL/Flux/SD3). Must be divisible by 8.
overlap	Overlap between patches as fraction of tile_size, 0.0-0.5 (default 0.125).
img2img_strength	If not NULL, run a final img2img pass over the stitched image at this denoising strength (e.g. 0.3) to harmonize seams. Requires vae_decode_only = FALSE in the context. Default NULL (disabled).
sample_method	Sampling method (see SAMPLE_METHOD)
sample_steps	Number of sampling steps (default 20)
cfg_scale	Classifier-free guidance scale (default 7.0)
seed	Base random seed. Each patch gets seed + patch_index. Use -1 for random.
scheduler	Scheduler type (see SCHEDULER)
clip_skip	Number of CLIP layers to skip (-1 = auto)
eta	Eta parameter for DDIM-like samplers
vae_mode	VAE tiling mode for the harmonization pass (default "auto": VRAM-aware, see sd_txt2img).
vae_auto_threshold	Pixel area fallback threshold for auto VAE tiling when VRAM query is unavailable
vae_tile_size	Tile size for VAE tiling (default 64)
vae_tile_overlap	Overlap for VAE tiling (default 0.25)

Value

SD image (list with width, height, channel, data)

Examples

## Not run: 
ctx <- sd_ctx("sd15.safetensors", model_type = "sd1")
img <- sd_txt2img_highres(ctx, "a panoramic mountain landscape",
                          width = 2048, height = 1024)
sd_save_image(img, "panorama.png")

## End(Not run)

sd2R documentation built on March 30, 2026, 5:08 p.m.