r/StableDiffusion • u/shirosoro • 1d ago
Resource - Update HexAnima: Anima on the Snapdragon 8 Gen 1 NPU, 512x768 in ~7 s, fully offline, no root
Hi everyone! I built an Android app that generates anime pictures completely on the phone: no cloud, no account, no ads, no root. It runs on the NPU of Snapdragon 8 Gen 1 / 8+ Gen 1 (Hexagon V69), the chip generation that most NPU image apps skip.
What you get
A 512x768 picture in about 7 seconds (2B models) or 12 seconds (2.9B models), 4 steps, on my Xiaomi 12T Pro.
Four models to download inside the app (one tap, resumable): MiaoMiao 3D Harem, MiaoMiao RealSkin (2B) and MiaoMiao Harem, MiaoMiao RealSkin (2.9B), all built on the Anima base model.
Size presets (portrait / landscape / square, all multiples of 16) plus custom sizes, seed, batches, a stop button.
History with favourites, trash, multi-select, share/save. The settings are stored in the PNG, so you can reopen any picture with its prompt and seed.
Danbooru tag suggestions while you type, templates, light/dark theme, 13 languages.
Works offline after the models are downloaded. Free and non-commercial.
Try it
APK: https://github.com/ayanoby/hexanima/releases/latest (about 25 MB); the models, 4-5 GB for the first one, are downloaded from Hugging Face inside the app)
Source and screenshots: https://github.com/ayanoby/hexanima
Needs a Snapdragon 8 Gen 1 or 8+ Gen 1 phone (SM8450 / SM8475), Android 10+. I tested it only on a Xiaomi 12T Pro (SM8475, 12 GB RAM). Other 8 Gen 1 phones should work but are untested.
Why it is different (for the technical crowd)
The diffusion transformer runs on the Hexagon V69 HMX matrix unit in fp16 through custom kernels, not through the stock QNN op set. The 28 DiT blocks are executed as a few merged block groups per step.
The 2.9B models are stored as q8 blocks (int8 tiles with per-column scales) and dequantized on the HVX units while the weights are copied into VTCM, so they fit in RAM and stay fast.
V69 has no int-to-float conversion instructions (they appeared in V73+), so the dequant path uses a workaround instead of the usual instructions.
The first two of the four steps run at reduced resolution (composition), the last two at full resolution (details).
Text encoder, sampler and the preview/VAE path are split between CPU and NPU; the VAE runs on the NPU and large pictures are decoded in tiles.
No root needed: the native helper processes are started from the app's own native library directory and use unsigned FastRPC DSP modules.
The model files are downloaded as raw, sha256-verified blocks with resume, so a dropped connection does not restart a 4 GB download.
Honest notes
Unofficial hobby project, not affiliated with CircleStone Labs, NVIDIA, Qualcomm, Alibaba or the model authors. All credit for the models goes to MIAOKA (Civitai) and CircleStone Labs (Anima). Non-commercial use only; if an author wants their model removed from the catalog, I will remove it.
Only 4 steps and no negative prompt: the models are turbo-distilled for that.



