feat(provider): add Tencent Cloud COS image provider

Author: wenyiqing

docs/content/3.providers/tencent-cloud.md

@@ -0,0 +1,149 @@
+---
+title: Tencent Cloud
+description: Use Tencent Cloud COS imageMogr2 for image processing.
+links:
+  - label: Source
+    icon: i-simple-icons-github
+    to: https://github.com/nuxt/image/blob/main/src/runtime/providers/tencentCloud.ts
+    size: xs
+---
+
+Integration with Tencent Cloud COS Cloud Infinite (CI) image processing (`imageMogr2`). Supports resizing, cropping, rotation, format conversion, quality control, Gaussian blur, sharpening, and more.
+
+## Setup
+
+Set the bucket domain as `baseURL` in `nuxt.config.ts`:
+
+```ts [nuxt.config.ts]
+export default defineNuxtConfig({
+  image: {
+    tencentCloud: {
+      baseURL: 'https://<bucket>.cos.<region>.myqcloud.com'
+    }
+  }
+})
+```
+
+::note
+`baseURL` should point to a publicly accessible COS bucket domain (or a bound CDN domain). No trailing slash is needed.
+::
+
+## Basic Usage
+
+```vue
+<NuxtImg
+  provider="tencentCloud"
+  src="/path/to/image.png"
+  width="600"
+  height="400"
+  fit="cover"
+  :modifiers="{ quality: 80, format: 'webp' }"
+/>
+```
+
+## Standard Modifiers
+
+All 7 standard NuxtImg modifiers are mapped to COS imageMogr2:
+
+| Modifier | COS Mapping | Description |
+|---|---|---|
+| `width` / `height` | `/thumbnail/<W>x<H>` | Proportional scaling, affected by `fit` |
+| `fit` | thumbnail suffix | `contain` → `<W>x<H>`, `cover` → `!<W>x<H>r`, `fill` → `<W>x<H>!` |
+| `quality` | `/quality/<Q>` | Quality 1-100 |
+| `format` | `/format/<f>` | Output format, `jpeg` is auto-mapped to `jpg` |
+| `background` | `/pad/1/color/<base64>` | Used with scaling, fills background color |
+| `blur` | `/blur/<n>x<n>` | Gaussian blur |
+
+## COS Extended Modifiers
+
+Pass Tencent Cloud-specific image processing parameters via the `:modifiers` prop:
+
+| Modifier | COS Mapping | Description |
+|---|---|---|
+| `crop` | `/crop/<W>x<H>` | Regular crop (independent of scaling) |
+| `gravity` | `/gravity/<pos>` | Crop anchor: center, north, south, west, east, northwest, etc. |
+| `dx` / `dy` | `/dx/<n>/dy/<n>` | Crop offset |
+| `iradius` | `/iradius/<r>` | Inscribed circle crop radius |
+| `scrop` | `/scrop/<W>x<H>` | Smart face crop |
+| `rotate` | `/rotate/<deg>` | Clockwise rotation 0-360° |
+| `autoOrient` | `/auto-orient` | Auto-rotate based on EXIF orientation |
+| `sharpen` | `/sharpen/<v>` | Sharpen |
+| `strip` | `/strip` | Strip EXIF metadata |
+| `interlace` | `/interlace/1` | Progressive JPEG/GIF |
+| `pad` | `/pad/1` | Pad mode (used with background) |
+
+## Examples
+
+### Resize + Format + Quality
+
+```vue
+<NuxtImg
+  provider="tencentCloud"
+  src="/photos/banner.png"
+  width="1200"
+  height="500"
+  fit="cover"
+  :modifiers="{ quality: 85, format: 'webp' }"
+/>
+```
+
+Generated URL: `?imageMogr2/thumbnail/!1200x500r/quality/85/format/webp`
+
+### Crop + Gravity
+
+```vue
+<NuxtImg
+  provider="tencentCloud"
+  src="/photos/portrait.jpg"
+  :modifiers="{ crop: '300x300', gravity: 'center' }"
+/>
+```
+
+Generated URL: `?imageMogr2/crop/300x300/gravity/center`
+
+### Rotate + Sharpen + Strip Metadata
+
+```vue
+<NuxtImg
+  provider="tencentCloud"
+  src="/photos/landscape.jpg"
+  :modifiers="{ rotate: 90, sharpen: 70, strip: true }"
+/>
+```
+
+Generated URL: `?imageMogr2/rotate/90/sharpen/70/strip`
+
+### Gaussian Blur (Placeholder Effect)
+
+```vue
+<NuxtImg
+  provider="tencentCloud"
+  src="/photos/hero.jpg"
+  width="100"
+  :modifiers="{ blur: 20, quality: 10 }"
+/>
+```
+
+Generated URL: `?imageMogr2/thumbnail/100x/quality/10/blur/20x20`
+
+### Smart Face Crop
+
+```vue
+<NuxtImg
+  provider="tencentCloud"
+  src="/photos/group.jpg"
+  :modifiers="{ scrop: '200x200' }"
+/>
+```
+
+Generated URL: `?imageMogr2/scrop/200x200`
+
+## References
+
+- [COS imageMogr2 Scaling](https://cloud.tencent.com/document/product/436/44880)
+- [COS imageMogr2 Cropping](https://cloud.tencent.com/document/product/436/44881)
+- [COS imageMogr2 Rotation](https://cloud.tencent.com/document/product/436/44882)
+- [COS imageMogr2 Format Conversion](https://cloud.tencent.com/document/product/436/44883)
+- [COS imageMogr2 Quality](https://cloud.tencent.com/document/product/436/44884)
+- [COS imageMogr2 Gaussian Blur](https://cloud.tencent.com/document/product/436/44885)
+- [COS imageMogr2 Sharpen](https://cloud.tencent.com/document/product/436/44886)