Added full support of rendering table

Todo: test with resize

src/components/scroller.ts

@@ -1,5 +1,12 @@
 import { Spreadsheet } from "../main"
 
+export interface ViewportRect {
+    top: number
+    left: number
+    right: number
+    bottom: number
+}
+
 export class Scroller {
     element: HTMLDivElement
     private verticalScroller: HTMLDivElement
@@ -17,6 +24,29 @@ export class Scroller {
         this.element.style.width = this.root.config.view.width + 'px'
 
         this.updateScrollerSize()   //* Init size set
+
+        this.element.addEventListener('scroll', this.handleScroll)
+    }
+
+    handleScroll = () => {
+        const rect = this.getViewportBoundlingRect()
+        this.root.viewport.updateValues(rect)
+
+        this.root.renderSheet()
+    }
+
+    getViewportBoundlingRect(): ViewportRect {
+        const { scrollTop, scrollLeft } = this.element
+        const { height, width } = this.element.getBoundingClientRect()
+        const bottom = scrollTop + height
+        const right = scrollLeft + width
+
+        return {
+            top: scrollTop,
+            left: scrollLeft,
+            bottom,
+            right
+        }
     }
 
     buildComponent() {

src/components/sheet.ts

@@ -33,15 +33,27 @@ export class Sheet {
     }
 
     renderSheet() {
-        const {columns, rows} = this.root.config
-        const lastColIdx = columns.length - 1
-        const lastRowIdx = rows.length - 1
+        const firstRowIdx = this.root.viewport.firstRow
+        const lastColIdx = this.root.viewport.lastCol + 3
+        const lastRowIdx = this.root.viewport.lastRow + 3
+        const firstColIdx = this.root.viewport.firstCol
+
+        console.log()
+
+        let rowsCount = 0
+
+        for(let row = firstRowIdx; row <= lastRowIdx; row++) {
+
+            for(let col = firstColIdx; col <= lastColIdx; col++ ) {
+                if(!this.root.config.columns[col] || !this.root.config.rows[row]) break;  //* Prevent read undefined
 
-        for(let row = 0; row <= lastRowIdx; row++) {
-            for(let col = 0; col <= lastColIdx; col++ ) {
                 this.renderCell({column: col, row})
             }
+
+            rowsCount++;
         }
+
+        console.log(`Rendered ${rowsCount} rows!`)
     }
 
 }

src/components/viewport.ts

@@ -1,3 +0,0 @@
-export class Viewport {
-    
-}

src/main.ts

@@ -7,6 +7,7 @@ import { Toolbar } from "./components/toolbar";
 import { Cell } from "./modules/cell";
 import { Config, ViewProperties } from "./modules/config";
 import { Styles } from "./modules/styles";
+import { Viewport } from "./modules/viewport";
 import './scss/main.scss'
 import { createSampleConfig, createSampleData } from "./utils/createData";
 
@@ -37,21 +38,24 @@ export class Spreadsheet {
     public styles: Styles
     public config: Config
     public data: Cell[][]
+    public viewport: Viewport
 
     constructor(target: string | HTMLElement, props?: SpreadsheetConstructorProperties) {
-        const config = createSampleConfig(40, 40)
+        const config = createSampleConfig(150, 150)
         if(props?.view) {
             config.view = props.view
         }
         
         this.config = new Config(config)
         this.sheet = new Sheet(this)
-        const data = createSampleData(40, 40)
+        const data = createSampleData(150, 150)
         this.table = new Table(this)
         this.scroller = new Scroller(this)
         this.toolbar = new Toolbar(this)
         this.header = new Header(this)
         this.editor = new Editor(this)
+        this.viewport = new Viewport(this, this.scroller.getViewportBoundlingRect())
+
 
         this.data = data
         this.styles = new Styles()

src/modules/cell.ts

@@ -31,11 +31,22 @@ export class Cell {
     }
 
     render(root: Spreadsheet) {
-        const {height, width, x, y} = new RenderBox(root.config, this.position)
+        let {height, width, x, y} = new RenderBox(root.config, this.position)
         const { ctx } = root
+
+        y -= root.viewport.top
+        x -= root.viewport.left
+
+        ctx.clearRect(x, y, width, height)
         ctx.fillStyle = 'white'
         ctx.strokeStyle = 'black'
         ctx.fillRect(x + 1, y + 1, width - 1, height - 1)
         ctx.strokeRect(x, y, width, height)
+
+        ctx.fillStyle = 'black'
+        ctx.textAlign = 'left'
+        ctx.font = '16px Arial'
+        ctx.textBaseline = 'middle'
+        ctx.fillText(this.displayValue, x + 2, y + height / 2, width)
     }
 }

src/modules/viewport.ts

@@ -0,0 +1,107 @@
+import { Spreadsheet } from "../main"
+
+export type ViewportConstructorProps = {
+    top: number
+    left: number
+    right: number
+    bottom: number
+}
+
+export class Viewport {
+    root: Spreadsheet
+
+    top: number
+    left: number
+    right: number
+    bottom: number
+
+    firstRow: number
+    lastRow: number
+    firstCol: number
+    lastCol: number
+
+    constructor(root: Spreadsheet, props: ViewportConstructorProps) {
+        this.root = root
+
+        this.top = props.top
+        this.left = props.left
+        this.right = props.right
+        this.bottom = props.bottom
+
+        this.firstRow = this.getFirstRow()
+        this.lastCol = this.getFirstRow()   //!Temp
+        this.firstCol = this.getFirstRow()  //!Temp
+        this.lastRow = this.getLastRow()
+
+        this.updateValues({
+            top: 0,
+            left: 0,
+            right: this.root.viewProps.width,
+            bottom: this.root.viewProps.height
+        })
+    }
+
+    updateValues(props: ViewportConstructorProps) {
+        this.top = props.top
+        this.left = props.left
+        this.right = props.right
+        this.bottom = props.bottom
+
+        this.firstRow = this.getFirstRow()
+        this.lastRow = this.getLastRow()
+        this.firstCol = this.getFirstCol()
+        this.lastCol = this.getLastCol()
+
+        console.log({ first: this.firstCol, last: this.lastCol })
+    }
+
+    /** Get index of first row in viewport */
+    private getFirstRow(): number {
+        let rowIdx = 0
+        for (let idx = 0, currHeight = 0; currHeight <= this.top; idx++) {
+            currHeight += this.root.config.rows[idx].height
+            rowIdx = idx
+        }
+        return rowIdx
+    }
+
+    private getLastRow(): number {
+        let rowIdx = this.getFirstRow()
+        let height = this.top
+
+        while (height <= this.bottom) {
+            height += this.root.config.rows[rowIdx].height
+            if (height >= this.bottom) break;
+            rowIdx++;
+        }
+
+        return rowIdx
+    }
+
+    private getFirstCol(): number {
+        let colIdx = 0;
+        let currWidth = 0
+
+        while (currWidth <= this.left) {
+            currWidth += this.root.config.columns[colIdx].width
+            if (currWidth >= this.left) break;
+            colIdx += 1
+        }
+
+        return colIdx
+    }
+
+    private getLastCol(): number {
+        let colIdx = this.getFirstCol()
+        let width = this.left
+
+        while (width <= this.right) {
+            width += this.root.config.columns[colIdx].width
+            if (width >= this.right) break;
+            colIdx++;
+        }
+
+        return colIdx
+    }
+
+}