diff --git a/canvas.go b/canvas.go index 3636c4b..96cb322 100644 --- a/canvas.go +++ b/canvas.go @@ -1,6 +1,7 @@ package canvas import ( + "image" "unsafe" "github.com/tfriedel6/lm" @@ -20,6 +21,12 @@ type Canvas struct { lineWidth float32 } path []pathPoint + text struct { + font *Font + size float32 + target *image.RGBA + tex uint32 + } } type pathPoint struct { diff --git a/color.go b/color.go index a04eb37..48bc534 100644 --- a/color.go +++ b/color.go @@ -7,7 +7,7 @@ import ( "strings" ) -func colorToGL(color color.Color) (r, g, b, a float32) { +func colorGoToGL(color color.Color) (r, g, b, a float32) { ir, ig, ib, ia := color.RGBA() r = float32(ir) / 65535 g = float32(ig) / 65535 @@ -16,6 +16,35 @@ func colorToGL(color color.Color) (r, g, b, a float32) { return } +func colorGLToGo(r, g, b, a float32) color.Color { + if r < 0 { + r = 0 + } else if r > 1 { + r = 1 + } + if g < 0 { + g = 0 + } else if g > 1 { + g = 1 + } + if b < 0 { + b = 0 + } else if b > 1 { + b = 1 + } + if a < 0 { + a = 0 + } else if a > 1 { + a = 1 + } + return color.RGBA{ + R: uint8(r * 255), + G: uint8(g * 255), + B: uint8(b * 255), + A: uint8(a * 255), + } +} + func parseHexRune(rn rune) (int, bool) { switch { case rn >= '0' && rn <= '9': @@ -93,7 +122,7 @@ func parseColor(value ...interface{}) (r, g, b, a float32, ok bool) { if len(value) == 1 { switch v := value[0].(type) { case color.Color: - r, g, b, a = colorToGL(v) + r, g, b, a = colorGoToGL(v) ok = true return case [3]float32: diff --git a/images.go b/images.go index 7fe97ab..343c6fc 100644 --- a/images.go +++ b/images.go @@ -43,6 +43,7 @@ func LoadImage(src interface{}) (*Image, error) { func loadImageRGBA(src *image.RGBA) (*Image, error) { img := &Image{w: src.Bounds().Dx(), h: src.Bounds().Dy()} gli.GenTextures(1, &img.tex) + gli.ActiveTexture(gl_TEXTURE0) gli.BindTexture(gl_TEXTURE_2D, img.tex) gli.TexParameteri(gl_TEXTURE_2D, gl_TEXTURE_MIN_FILTER, gl_LINEAR_MIPMAP_LINEAR) gli.TexParameteri(gl_TEXTURE_2D, gl_TEXTURE_MAG_FILTER, gl_LINEAR) @@ -75,6 +76,7 @@ func loadImageRGBA(src *image.RGBA) (*Image, error) { func loadImageGray(src *image.Gray) (*Image, error) { img := &Image{w: src.Bounds().Dx(), h: src.Bounds().Dy()} gli.GenTextures(1, &img.tex) + gli.ActiveTexture(gl_TEXTURE0) gli.BindTexture(gl_TEXTURE_2D, img.tex) gli.TexParameteri(gl_TEXTURE_2D, gl_TEXTURE_MIN_FILTER, gl_LINEAR_MIPMAP_LINEAR) gli.TexParameteri(gl_TEXTURE_2D, gl_TEXTURE_MAG_FILTER, gl_LINEAR) @@ -107,6 +109,7 @@ func loadImageGray(src *image.Gray) (*Image, error) { func loadImageConverted(src image.Image) (*Image, error) { img := &Image{w: src.Bounds().Dx(), h: src.Bounds().Dy()} gli.GenTextures(1, &img.tex) + gli.ActiveTexture(gl_TEXTURE0) gli.BindTexture(gl_TEXTURE_2D, img.tex) gli.TexParameteri(gl_TEXTURE_2D, gl_TEXTURE_MIN_FILTER, gl_LINEAR_MIPMAP_LINEAR) gli.TexParameteri(gl_TEXTURE_2D, gl_TEXTURE_MAG_FILTER, gl_LINEAR) diff --git a/text.go b/text.go new file mode 100644 index 0000000..a450314 --- /dev/null +++ b/text.go @@ -0,0 +1,99 @@ +package canvas + +import ( + "errors" + "image" + "io/ioutil" + "unsafe" + + "github.com/golang/freetype" + "github.com/golang/freetype/truetype" + "golang.org/x/image/math/fixed" +) + +var fontRenderingContext = freetype.NewContext() + +type Font struct { + font *truetype.Font +} + +func LoadFont(src interface{}) (*Font, error) { + switch v := src.(type) { + case *truetype.Font: + return &Font{font: v}, nil + case string: + data, err := ioutil.ReadFile(v) + if err != nil { + return nil, err + } + font, err := freetype.ParseFont(data) + if err != nil { + return nil, err + } + return &Font{font: font}, nil + case []byte: + font, err := freetype.ParseFont(v) + if err != nil { + return nil, err + } + return &Font{font: font}, nil + } + return nil, errors.New("Unsupported source type") +} + +func (cv *Canvas) SetFont(font *Font, size float32) { + cv.text.font = font + cv.text.size = size +} + +func (cv *Canvas) FillText(str string, x, y float32) { + cv.activate() + + if cv.text.target == nil || cv.text.target.Bounds().Dx() != cv.w || cv.text.target.Bounds().Dy() != cv.h { + if cv.text.tex != 0 { + gli.DeleteTextures(1, &cv.text.tex) + } + cv.text.target = image.NewRGBA(image.Rect(0, 0, cv.w, cv.h)) + gli.GenTextures(1, &cv.text.tex) + gli.ActiveTexture(gl_TEXTURE0) + gli.BindTexture(gl_TEXTURE_2D, cv.text.tex) + gli.TexParameteri(gl_TEXTURE_2D, gl_TEXTURE_MIN_FILTER, gl_NEAREST) + gli.TexParameteri(gl_TEXTURE_2D, gl_TEXTURE_MAG_FILTER, gl_NEAREST) + gli.TexParameteri(gl_TEXTURE_2D, gl_TEXTURE_WRAP_S, gl_CLAMP_TO_EDGE) + gli.TexParameteri(gl_TEXTURE_2D, gl_TEXTURE_WRAP_T, gl_CLAMP_TO_EDGE) + } + + for i := range cv.text.target.Pix { + cv.text.target.Pix[i] = 0 + } + + fontRenderingContext.SetFont(cv.text.font.font) + fontRenderingContext.SetFontSize(float64(cv.text.size)) + fontRenderingContext.SetSrc(image.NewUniform(colorGLToGo(cv.fill.r, cv.fill.g, cv.fill.b, cv.fill.a))) + fontRenderingContext.SetDst(cv.text.target) + fontRenderingContext.SetClip(cv.text.target.Bounds()) + fontRenderingContext.DrawString(str, fixed.Point26_6{X: fixed.Int26_6(x*64 + 0.5), Y: fixed.Int26_6(y*64 + 0.5)}) + + gli.BlendFunc(gl_ONE, gl_ONE_MINUS_SRC_ALPHA) + + gli.ActiveTexture(gl_TEXTURE0) + gli.BindTexture(gl_TEXTURE_2D, cv.text.tex) + gli.TexImage2D(gl_TEXTURE_2D, 0, gl_RGBA, int32(cv.w), int32(cv.h), 0, gl_RGBA, gl_UNSIGNED_BYTE, gli.Ptr(&cv.text.target.Pix[0])) + + gli.UseProgram(tr.id) + gli.Uniform1i(tr.image, 0) + + gli.BindBuffer(gl_ARRAY_BUFFER, buf) + data := [16]float32{-1, -1, -1, 1, 1, 1, 1, -1, 0, 1, 0, 0, 1, 0, 1, 1} + gli.BufferData(gl_ARRAY_BUFFER, len(data)*4, unsafe.Pointer(&data[0]), gl_STREAM_DRAW) + + gli.VertexAttribPointer(tr.vertex, 2, gl_FLOAT, false, 0, nil) + gli.VertexAttribPointer(tr.texCoord, 2, gl_FLOAT, false, 0, gli.PtrOffset(8*4)) + gli.EnableVertexAttribArray(tr.vertex) + gli.EnableVertexAttribArray(tr.texCoord) + gli.DrawArrays(gl_TRIANGLE_FAN, 0, 4) + gli.DisableVertexAttribArray(tr.vertex) + gli.DisableVertexAttribArray(tr.texCoord) + + gli.BlendFunc(gl_SRC_ALPHA, gl_ONE_MINUS_SRC_ALPHA) +}