feat: improved text pos. fallback mechanism

banner.go

@@ -40,7 +40,6 @@ func NewTextData(text string, size float64, multiline bool) *TextData {
 	return &TextData{splits, size, false, -1, -1, -1, -1}
 }
 
-// Consistent outline thickness based on font size
 func getOutlineThickness(size float64) int {
 	thickness := int(size / 8)
 	if thickness < 1 {
@@ -51,7 +50,6 @@ func getOutlineThickness(size float64) int {
 	return thickness
 }
 
-// Actual bounding box for text including outline
 func getTextBounds(text []string, size float64) (width, height int) {
 	face, err := createFontFace(size)
 	if err != nil {
@@ -146,8 +144,7 @@ func drawTextWithOutline(canvas *image.RGBA, text []string, x, y int, textColor,
 	}
 }
 
-// Place all elements to canvas without overlaps
-func findTextPositions(textData []*TextData) {
+func findTextPositions(textData []*TextData, filename string) {
 	padding := 10
 
 	for i, data := range textData {
@@ -182,7 +179,7 @@ func findTextPositions(textData []*TextData) {
 			y := rand.IntN(maxY-minY+1) + minY
 
 			// bounding box for cur. text
-			currentRect := struct{ x, y, w, h int }{
+			curRect := struct{ x, y, w, h int }{
 				x: x,
 				y: y,
 				w: w,
@@ -204,7 +201,7 @@ func findTextPositions(textData []*TextData) {
 					h: other.H + padding,
 				}
 
-				if rectsOverlap(currentRect, otherRect) {
+				if rectsOverlap(curRect, otherRect) {
 					overlaps = true
 					break
 				}
@@ -219,35 +216,84 @@ func findTextPositions(textData []*TextData) {
 			}
 		}
 
-		// fallback: use grid positioning
+		// fallback: place to a free corner
 		if !placed {
-			log.Warnf("Using fallback position for text '%v'", data.Text)
+			log.Debugf("Using fallback position for text '%s' in '%s'", data.Text, filename)
 
-			gridCols := 2
-			col := i % gridCols
-			row := i / gridCols
-
-			cellWidth := config.BannerWidth / gridCols
-			cellHeight := config.BannerHeight / 3 // NOTE: assuming max 3 rows
-
-			data.X = col*cellWidth + (cellWidth-w)/2
-			data.Y = row*cellHeight + (cellHeight-h)/2
-
-			// ensure within bounds
-			if data.X < padding {
-				data.X = padding
-			}
-			if data.Y < padding {
-				data.Y = padding
-			}
-			if data.X+w > config.BannerWidth-padding {
-				data.X = config.BannerWidth - w - padding
-			}
-			if data.Y+h > config.BannerHeight-padding {
-				data.Y = config.BannerHeight - h - padding
+			corners := []struct {
+				name string
+				x, y int
+			}{
+				{"top-left", padding, padding},
+				{"top-right", config.BannerWidth - w - padding, padding},
+				{"bottom-left", padding, config.BannerHeight - h - padding},
+				{"bottom-right", config.BannerWidth - w - padding, config.BannerHeight - h - padding},
 			}
 
+			bestCorner := 0
+			minOverlapArea := int(^uint(0) >> 1) // max. int
+
+			// try each corner and find the one with least overlap
+			for cornerIdx, corner := range corners {
+				curRect := struct{ x, y, w, h int }{
+					x: corner.x,
+					y: corner.y,
+					w: w,
+					h: h,
+				}
+
+				totalOverlapArea := 0
+
+				// calculate total overlap area with existing texts
+				for j := 0; j < i; j++ {
+					other := textData[j]
+					if !other.Positioned {
+						continue
+					}
+
+					otherRect := struct{ x, y, w, h int }{
+						x: other.X,
+						y: other.Y,
+						w: other.W,
+						h: other.H,
+					}
+
+					if rectsOverlap(curRect, otherRect) {
+						// intersection rectangle
+						overlapLeft := max(curRect.x, otherRect.x)
+						overlapTop := max(curRect.y, otherRect.y)
+						overlapRight := min(curRect.x+curRect.w, otherRect.x+otherRect.w)
+						overlapBottom := min(curRect.y+curRect.h, otherRect.y+otherRect.h)
+
+						overlapWidth := overlapRight - overlapLeft
+						overlapHeight := overlapBottom - overlapTop
+						overlapArea := overlapWidth * overlapHeight
+
+						totalOverlapArea += overlapArea
+					}
+
+					if totalOverlapArea < minOverlapArea {
+						minOverlapArea = totalOverlapArea
+						bestCorner = cornerIdx
+					}
+
+					// if no overlap, use the pos. immediately
+					if totalOverlapArea == 0 {
+						break
+					}
+				}
+			}
+
+			// place at the best corner
+			data.X = corners[bestCorner].x
+			data.Y = corners[bestCorner].y
 			data.Positioned = true
+
+			if minOverlapArea > 0 {
+				log.Debugf("Placed text '%v' at %s corner with some overlap (area: %d)", data.Text, corners[bestCorner].name, minOverlapArea)
+			} else {
+				log.Debugf("Placed text '%v' at %s corner with no overlap", data.Text, corners[bestCorner].name)
+			}
 		}
 	}
 }
@@ -363,9 +409,10 @@ func genPerlinBG() *image.RGBA {
 }
 
 func genBanner(textData []*TextData) error {
+	fn := fmt.Sprintf("banner_%d.png", time.Now().UnixMicro())
 	canvas := genPerlinBG()
 
-	findTextPositions(textData)
+	findTextPositions(textData, fn)
 
 	for _, td := range textData {
 		if td.Positioned {
@@ -374,7 +421,6 @@ func genBanner(textData []*TextData) error {
 		}
 	}
 
-	fn := fmt.Sprintf("banner_%d.png", time.Now().UnixMicro())
 	fp := filepath.Join(bannersDir, fn)
 	file, err := os.Create(fp)
 	if err != nil {